Document and Entity Information [Abstract] Document And Entity Information [Abstract] Statement [Table] Statement [Line Items] Document Type Amendment Flag Document Period End Date Document Fiscal Year Focus Document Fiscal Period Focus Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Entity Filer Category Entity Common Stock, Shares Outstanding Consolidated Balance Sheets [Abstract] Assets Property, plant and equipment, at cost Less: accumulated depreciation Net property, plant and equipment Net property, plant and equipment Current assets: Cash and cash equivalents Cash and cash equivalents at end of period Cash and cash equivalents at beginning of period Accounts receivable and unbilled revenues, net Inventory, materials and supplies Prepayments and other current assets Assets Held-for-sale, Not Part of Disposal Group, Current Assets held for sale Total current assets Total current assets Regulatory Assets Noncurrent Regulatory assets Deferred Costs and Other Assets Deferred charges and other assets Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Investment in joint venture Goodwill Balance Balance Goodwill Total Assets Total assets Total assets Liabilities and Equity Stockholders' equity: Common stock authorized and issued Common stock at $.50 par value, authorized 300,000,000 shares, issued 180,635,368 and 180,311,345 as of June 30, 2017 and December 31, 2016 Common stock, $.50 par value Additional Paid In Capital Common Stock Capital in excess of par value Retained Earnings Accumulated Deficit Retained earnings Treasury stock, at cost Treasury stock, at cost, 2,984,264 and 2,916,969 shares as of June 30, 2017 and December 31, 2016 Treasury stock, at cost Accumulated Other Comprehensive Income Loss Net Of Tax Accumulated other comprehensive income Accumulated other comprehensive income Total Aqua America stockholders' equity Balance Balance Total stockholders' equity Debt Instrument Carrying Amount Noncurrent Debt Instrument Carrying Amount Noncurrent Long-term debt, excluding current portion Unamortized Debt Issuance Expense Less: debt issuance costs Long Term Debt Noncurrent Long-term debt, excluding current portion, net of debt issuance costs Commitments and contingencies 2009 Commitments and contingencies (See Note 13) Current liabilities: Current portion of long-term debt Loans payable Accounts payable Interest Payable, Current Accrued interest Accrued taxes Accrued Liabilities Current Other accrued liabilities Total current liabilities Total current liabilities Deferred credits and other liabilities: Deferred income taxes and investment tax credits Customers' advances for construction Customers' advances for construction Regulatory Liability Noncurrent Regulatory liabilities Other Liabilities Noncurrent Other Liabilities, Other than Long-term Debt, Noncurrent Total deferred credits and other liabilities Contributions in aid of construction Total liabilities and stockholders' equity Total liabilities and equity Common stock, par value Common stock, par value Common stock, shares authorized Common stock, shares issued Treasury stock, shares Consolidated Statements Of Net Income [Abstract] Operating revenues Cost and expenses: Operating expenses: Utilities Operating Expense Maintenance And Operations Operations and maintenance Operations and maintenance expense Depreciation Amortization Taxes other than income taxes Total taxes other than income Total expenses Total operating expenses Operating income Operating income Operating income Other expense (income): Interest expense, net Public Utilities Allowance For Funds Used During Construction Additions Allowance for funds used during construction Allowance for funds used during construction Gain Loss On Sale Of Other Assets Gain on sale of other assets Net Income (Loss) Attributable to Noncontrolling Interest, Joint Venture Partners Equity loss in joint venture Income from continuing operations before income taxes Income before income taxes Provision for income taxes Income tax expense (benefit) Net income attributable to common shareholders Net income Net income Net income (loss) Net Income Per Common Share [Abstract] Net income per common share: Earnings Per Share Basic Basic Earnings Per Share Diluted Diluted Weighted Average Number of Shares Outstanding Abstract Average common shares outstanding during the period: Basic Average common shares outstanding during the period for basic computation Diluted Average common shares outstanding during the period for diluted computation Cash dividends declared per common share Consolidated Statements Of Comprehensive Income [Abstract] Other comprehensive income, net of tax: Unrealized holding gain on investments, net of income tax Unrealized holding gain on investments, net of tax expense of $20 and $7 for the three months and $51 and $3 for the six months ended June 30, 2017 and 2016, respectively Reclassification adjustment for (gains) losses reported in net income Reclassification of gain on sale of investment to net income, net of tax of $30 for the six months ended June 30, 2016 Comprehensive income Comprehensive income Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax Income taxes arising from net unrealized holding gain on investments Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Tax Income tax benefit arising from reclassification adjustment for loss reported in net income Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, before Tax Pre-tax loss of reclassification adjustment for loss reported in net income Consolidated Statements of Capitalization [Abstract] Consolidated Statements Of Capitalization [Abstract] Debt Instrument [Axis] Debt Instrument Name [Domain] Debt Instrument, Name [Domain] Long Term Debt Of Subsidiaries zero point zero zero percentage to zero point nine nine percentage [Member] Long Term Debt Of Subsidiaries Zero Point Zero Zero Percentage To Zero Point Nine Nine Percentage [Member] Long-Term Debt Of Subsidiaries 0.00% To 0.99% [Member] Long Term Debt Of Subsidiaries one point zero zero percentage to one point nine nine percentage [Member] Long Term Debt Of Subsidiaries One Point Zero Zero Percentage To One Point Nine Nine Percentage [Member] Long-Term Debt Of Subsidiaries 1.00% To 1.99% [Member] Long Term Debt Of Subsidiaries two point zero zero percentage to two point nine nine percentage [Member] Long Term Debt Of Subsidiaries Two Point Zero Zero Percentage To Two Point Nine Nine Percentage [Member] Long-Term Debt Of Subsidiaries 2.00% To 2.99% [Member] Long Term Debt Of Subsidiaries three point zero zero percentage to three point nine nine percentage [Member] Long Term Debt Of Subsidiaries Three Point Zero Zero Percentage To Three Point Nine Nine Percentage [Member] Long-Term Debt Of Subsidiaries 3.00% To 3.99% [Member] Long Term Debt Of Subsidiaries four point zero zero percentage to four point nine nine percentage [Member] Long Term Debt Of Subsidiaries Four Point Zero Zero Percentage To Four Point Nine Nine Percentage [Member] Long-Term Debt Of Subsidiaries 4.00% To 4.99% [Member] Long Term Debt Of Subsidiaries five point zero zero percentage to five point nine nine percentage [Member] Long Term Debt Of Subsidiaries Five Point Zero Zero Percentage To Five Point Nine Nine Percentage [Member] Long-Term Debt Of Subsidiaries 5.00% To 5.99% [Member] Long Term Debt Of Subsidiaries six point zero zero percentage to six point nine nine percentage [Member] Long Term Debt Of Subsidiaries Six Point Zero Zero Percentage To Six Point Nine Nine Percentage [Member] Long-Term Debt Of Subsidiaries 6.00% To 6.99% [Member] Long Term Debt Of Subsidiaries seven point zero zero percentage to seven point nine nine percentage [Member] Long Term Debt Of Subsidiaries Seven Point Zero Zero Percentage To Seven Point Nine Nine Percentage [Member] Long-Term Debt Of Subsidiaries 7.00% To 7.99% [Member] Long Term Debt Of Subsidiaries eight point zero zero percentage to eight point nine nine percentage [Member] Long Term Debt Of Subsidiaries Eight Point Zero Zero Percentage To Eight Point Nine Nine Percentage [Member] Long-Term Debt Of Subsidiaries 8.00% To 8.99% [Member] Long Term Debt Of Subsidiaries nine point zero zero percentage to nine point nine nine percentage [Member] Long Term Debt Of Subsidiaries Nine Point Zero Zero Percentage To Nine Point Nine Nine Percentage [Member] Long-Term Debt Of Subsidiaries 9.00% To 9.99% [Member] Bank Note At One Point Nine Two One Percent [Member] Bank Note At One Point Nine Two One Percent [Member] Bank notes at 1.921% and 1.975% due 2017 and 2018 [Member] Notes Ranges B [Member] Notes Ranges B [Member] Notes ranging from 3.01% to 3.59% due 2027 through 2041 [Member] Notes Ranging From four point six two percentage to four point eight seven percentage [Member] Notes Ranging From Four Point Six Two Percentage To Four Point Eight Seven Percentage [Member] Notes Ranging From 4.62% To 4.87%, due 2017 through 2024 [Member] Notes Ranging From Five Point Zero One Percentage To Five Point Nine Five Percentage [Member] Notes Ranging From Five Point Zero One Percentage To Five Point Nine Five Percentage [Member] Notes Ranging From 5.20% To 5.95%, due 2018 through 2037 [Member] Long-term debt: Secured Debt Long-term debt of subsidiaries Other Notes Payable, Noncurrent Notes payable to bank under revolving credit agreement, variable rate, due 2017 Notes ranging from 4.62% to 4.87%, due 2013 through 2024 Unsecured notes payable Debt Instrument, Principal Outstanding Total long-term debt Total capitalization Total capitalization Range [Axis] Range [Member] Range [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Long Term Debt Of Subsidiaries Ten Point Zero Zero Percentage To Ten Point Nine Nine Percentage [Member] Long Term Debt Of Subsidiaries Ten Point Zero Zero Percentage To Ten Point Nine Nine Percentage [Member] Long-Term Debt Of Subsidiaries 10.00% To 10.99% [Member] Revolving Credit Agreement, Due B Revolving Credit Agreement Due B [Member] Revolving Credit Agreement, Due 2021 [Member] Notes B [Member] Notes B [Member] Notes at 3.01% due 2027 [Member] Notes C [Member] Notes C [Member] Notes at 3.59% due 2041 [Member] Interest Rate Interest Rate Interest rate Debt Instrument, Maturity Date, Year Debt Instrument, Maturity Date, Year Maturity date Maturity Consolidated Statement Of Equity [Abstract] Statement, Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Parent [Member] Parent [Member] Common Stock [Member] Common Stock [Member] Additional Paid In Capital [Member] Capital In Excess Of Par Value [Member] Retained Earnings [Member] Retained Earnings [Member] Treasury Stock [Member] Treasury Stock [Member] Accumulated Other Comprehensive Income [Member] Accumulated Other Comprehensive Income [Member] Other Comprehensive Income (Loss), Net of Tax Other comprehensive income, net of income tax of $51 Dividends paid Dividends Sale of stock (23,194 shares) Repurchase of stock (414,869 shares) Repurchase of stock (67,295 shares) Stock granted during period, value share-based compensation Equity compensation plan (160,279 shares) Stock Issued During Period, Value, Stock Options Exercised Exercise of stock options (140,550 shares) Treasury Stock Reissued at Lower than Repurchase Price, Share-based Compensation Treasury Stock Reissued at Lower than Repurchase Price, Share-based Compensation Stock-based compensation Cumulative Effect on Retained Earnings, Net of Tax Cumulative effect of change in accounting principle - windfall tax benefit Other Consolidated Statement Of Equity (Parenthetical) [Abstract] Other Comprehensive Income (Loss), Tax Other Comprehensive income, net of income tax Sale Of Stock, Shares Sale of stock, shares Repurchase Of Stock, Shares Repurchase of stock, shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Granted Granted, Number of Share Units Equity compensation plan, shares Exercise Of Stock Options, Shares Exercised, Shares Exercise of stock options, shares Consolidated Statements Of Cash Flow [Abstract] Cash flows from operating activities: Adjustments to reconcile net income to net cash flows from operating activities: Adjustments to reconcile net income to net cash flows from operating activities: Depreciation and amortization Deferred Income Tax Expense (Benefit), Total Deferred income taxes Provision for doubtful accounts Share Based Compensation Stock-based compensation Gain (Loss) on Sale of Business Loss (gain) on sale of utility system and market-based business unit Net decrease in receivables, inventory and prepayments Net change in receivables, inventory and prepayments Net decrease in payables, accrued interest, accrued taxes and other accrued liabilities Net change in payables, accrued interest, accrued taxes and other accrued liabilities Increase (Decrease) in Obligation, Pension and Other Postretirement Benefits Postretirement benefit contributions Increase Decrease In Other Operating Assets Other Net Cash Provided by (Used in) Operating Activities, Continuing Operations Net cash flows from operating activities Cash flows from investing activities: Payments to acquire property, plant and equipment Property, plant and equipment additions, including the debt component of allowance for funds used during construction of $1,543 and $1,097 Capital expenditures Payments to Acquire Waste Water Systems Acquisitions of utility systems and other, net Proceeds from sale of utility system and other Proceeds from sale of utility system and other Net proceeds from the sale of utility system and other assets Payments for (Proceeds from) Other Investing Activities Other Net Cash Provided by (Used in) Investing Activities, Continuing Operations Net cash flows used in investing activities Cash flows from financing activities: Proceeds from Advances for Construction, Financing Activities Proceeds from Advances for Construction, Financing Activities Customers' advances and contributions in aid of construction Repayments of Advances for Construction, Financing Activities Repayments of Advances for Construction, Financing Activities Repayments of customers' advances Net proceeds (repayments) of short-term debt Net proceeds of short-term debt Proceeds from long-term debt Repayments of long-term debt Repayments of long-term debt Change in cash overdraft position Proceeds from issuing common stock Proceeds from stock options exercised Proceeds from exercised stock options Share-based compensation windfall tax benefits Stock-based compensation windfall tax benefits Payments For Repurchase Of Common Stock Repurchase of common stock Payments Of Dividends Common Stock Dividends paid on common stock Proceeds from (Payments for) Other Financing Activities Other Net Cash Provided by (Used in) Financing Activities, Continuing Operations Net cash flows from (used in) financing activities Net increase in cash and cash equivalents Net change in cash and cash equivalents Non-cash investing activities: Property, plant and equipment additions purchased at the period end, but not yet paid for Non-Cash Customer Advances And Contributions In Aid Of Construction Non-Cash Customer Advances And Contributions In Aid Of Construction Non-cash customer advances and contributions in aid of construction Debt component of allowance for funds used during construction Debt component of allowance for funds used during construction Basis Of Presentation [Abstract] Organization Consolidation And Presentation of Financial Statements Disclosure [Text Block] Basis Of Presentation Goodwill [Abstract] Goodwill And Intangible Assets Disclosure Text Block Goodwill Acquisitions [Abstract] Business Combination Disclosure [Text Block] Acquisitions Assets Held For Sale [Abstract] Property, Plant and Equipment Disclosure [Text Block] Assets Held For Sale Capitalization [Abstract] Capitalization Disclosure [Text Block] Capitalization Disclosure [Text Block] Capitalization Fair Value Of Financial Instruments [Abstract] Fair Value Disclosures [Text Block] Fair Value Of Financial Instruments Earnings Per Share [Text Block] Net Income Per Common Share Stock-Based Compensation [Abstract] Disclosure Of Compensation Related Costs Share Based Payments Text Block Stock-Based Compensation Pension Plans And Other Postretirement Benefits [Abstract] Pension And Other Postretirement Benefits Disclosure [Text Block] Pension Plans And Other Postretirement Benefits Water and Wastewater Rates Water And Wastewater Rates [Abstract] Public Utilities Disclosure [Text Block] Water And Wastewater Rates Taxes Other than Income Taxes Taxes Other Than Income Taxes [Abstract] Utilities Operating Expenses, Taxes As In Annual Report [Text Block] Utilities Operating Expenses, Taxes As In Annual Report [Text Block] Taxes Other Than Income Taxes Segment Information [Abstract] Segment Reporting Disclosure [Text Block] Segment Information Commitments And Contingencies [Abstract] Commitments and Contingencies Disclosure [Text Block] Commitments And Contingencies Income Taxes [Abstract] Income Tax Disclosure Text Block Income Taxes Recent Accounting Pronouncements [Abstract] Schedule Of New Accounting Pronouncements And Changes In Accounting Principles [Text Block] Recent Accounting Pronouncements Schedule of Goodwill [Text Block] Schedule Of Goodwill Schedule of Capitalization [Table Text Block] Schedule Of Capitalization Fair Value, by Balance Sheet Grouping [Text Block] Schedule Of Carrying Amounts And Estimated Fair Values Of Long-Term Debt Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule Of Earnings Per Share Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Award Type and Plan Name [Axis] Share Based Compensation Arrangements By Share Based Payment Award Award Type And Plan Name [Domain] Share-based Compensation Arrangements by Share-based Payment Award, Award Type and Plan Name [Domain] Performance Share Units [Member] Performance Share Units [Member] Performance Share Units [Member] Restricted Stock Units R S U [Member] Restricted Stock Units [Member] Employee Stock Option [Member] Stock Options [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Schedule of Nonvested Performance-based Units Activity [Table Text Block] Summary Of PSU Transactions Schedule of Nonvested Restricted Stock Units Activity [Table Text Block] Summary Of RSU Transactions Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block] Summary Of Compensation Costs Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions [Table Text Block] Assumptions Used In The Pricing Model Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block] Summary Of Stock Option Transactions Schedule of Nonvested Share Activity [Table Text Block] Summary Of Nonvested Share Activity Schedule of Net Benefit Costs [Table Text Block] Components Of Net Periodic Benefit Costs Utilities Operating Expenses, Taxes As In Annual Report [Table Text Block] Utilities Operating Expenses, Taxes As In Annual Report [Table Text Block] Components Of Taxes Other Than Income Taxes Reconciliation of Revenue from Segments to Consolidated [Text Block] Company's Segment Information, Continuing Operations Reconciliation of Assets from Segment to Consolidated [Text Block] Company's Segment Information, Assets Schedule of Goodwill [Table] Goodwill [Line Items] Goodwill, Acquired During Period Goodwill acquired Reclassification Of Goodwill, Acquisition Adjustment Reclassification Of Goodwill, Acquisition Adjustment Reclassification to utility plant acquisition adjustment Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Axis] Business Acquisition Acquiree [Domain] Business Acquisition, Acquiree [Domain] Superior Water Company, Inc. [Member] Superior Water Company Inc. [Member] Superior Water Company, Inc. [Member] Wastewater Utility Systems In Various States [Member] Wastewater Utility Systems In Various States [Member] Water And Wastewater Utility Systems In Various States [Member] Business Acquisition [Line Items] Number of customers. Number of customers Business Combination, Consideration Transferred Total purchase price Business Acquisition, Equity Interest Issued or Issuable, Number of Shares Shares issued for acquisition Business Acquisition, Cost of Acquired Entity, Cash Paid Cash Paid Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment Acquired property, plant and equipment Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets Contributions in aid of construction Number Of Business Acquisitions Completed Number of acquisitions Disposal Groups, Including Discontinued Operations [Table] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Disposal Group, Including Discontinued Operation, Number Of Business Units Disposal Group, Including Discontinued Operation, Number Of Business Units Sale of business units Schedule of Long-term Debt Instruments [Table] Related Party [Axis] Related Party [Domain] Related Party [Domain] Aqua Pennsylvania, Inc [Member] Aqua Pennsylvania Inc [Member] Aqua Pennsylvania, Inc [Member] First Mortgage Bonds [Member] First Mortgage Bonds [Member] First Mortgage Bonds [Member] First Mortgage Bonds B [Member] First Mortgage Bonds B [Member] First Mortgage Bonds Due In 2042 [Member] First Mortgage Bonds C [Member] First Mortgage Bonds C [Member] First Mortgage Bonds Due In 2044 [Member] First Mortgage Bonds D [Member] First Mortgage Bonds D [Member] First Mortgage Bonds [Member] First Mortgage Bonds E [Member] First Mortgage Bonds E [Member] First Mortgage Bonds Due In 2055 [Member] First Mortgage Bonds F [Member] First Mortgage Bonds F [Member] First Mortgage Bonds Due In 2057 [Member] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Debt Instrument [Line Items] Face Amount Debt Instrument, Maturity Year Debt Instrument, Maturity Year Maturity Year Schedule of Capitalization [Table] Capitalization [Line Items] Long-term debt1 Amount Fair Value, by Balance Sheet Grouping [Table] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Loans Payable, Fair Value Disclosure Loans payable Investments, Fair Value Disclosure Mutual funds Measurement Basis [Axis] Portion At Fair Value Fair Value Disclosure [Member] Portion at Fair Value Measurement [Member] Carrying Reported Amount Fair Value Disclosure [Member] Carrying Amount [Member] Estimate Of Fair Value Fair Value Disclosure [Member] Estimated Fair Value [Member] Long Term Debt Fair Value Long-term debt Incremental Common Shares Attributable to Share-based Payment Arrangements Dilutive effect of employee stock-based compensation Two Thousand And Four Omnibus Equity Compensation Plan [Member] Two Thousand And Four Omnibus Equity Compensation Plan [Member] 2004 Plan [Member] Two Thousand Nine Omnibus Equity Compensation Plan [Member] Two Thousand Nine Omnibus Equity Compensation Plan [Member] 2009 Plan [Member] Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Number of shares authorized for issuance Maximum Number Of Shares May Be Issued Pursuant To Stock Awards, Stock Units And Other Stock-Based Awards Maximum Number Of Shares May Be Issued Pursuant To Stock Awards, Stock Units And Other Stock-Based Awards Maximum number of shares may be issued pursuant to stock awards, stock units and other stock-based awards Share-based Compensation Arrangement by Share-based Payment Award, Maximum Shares Per Employee Maximum number of shares subject to grants to any one individual in any one year Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Underlying stock option and restricted stock awards available for grant Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage Vesting percentage Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period Vesting period, start, in years Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Vesting period, in years Restricted Stock Units Restricted Period Restricted Stock Units Restricted Period Restricted period Percentage of target award amount the participant may earn Percentage Of Target Award Amount The Participant May Earn Percentage of target award amount the grantee may earn Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Granted, Weighted Average Fair Value Weighted average fair value of stock awards granted Share based compensation arrangement by share based payment award amortization period of fair value of shares Share based compensation arrangement by share based payment award Amortization Period Of Fair Value of Shares Amortization period of fair value of shares, in months Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Nonvested share units at end of period, Number of Share Units Nonvested share units at beginning of period, Number of Share Units Share based compensation arrangement by share based payment award equity instruments other than options performance criteria adjustment Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Performance Criteria Adjustment Performance criteria adjustment, Number of Share Units Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Forfeited, Number of Share Units Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Stock units vested and issued, Number of Share Units Share units vested in prior period and issued in current period, Number of Share Units Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period Share units issued, Number of Share Units Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Nonvested share units at end of period, Weighted Average Fair Value Nonvested share units at beginning of period, Weighted Average Fair Value Share based compensation arrangement by share based payment award equity instruments other than options performance criteria adjustment, weighted average grant date fair value Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Performance Criteria Adjustment, Weighted Average Grant Date Fair Value Performance criteria adjustment, Weighted Average Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period, Weighted Average Grant Date Fair Value Forfeited, Weighted Average Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Stock units vested and issued, Weighted Average Fair Value Share based compensation arrangement by share based payment award shares issued in Period, weighted average grant date fair value Share Based Compensation Arrangement By Share Based Payment Award Shares Issued In Period, Weighted Average Grant Date Fair Value Share units issued, Weighted Average Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost Stock-based compensation within operations and maintenance expense Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Income tax benefit Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Expected term (years) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Risk-free interest rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Expected volatility Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Dividend yield Share-based Compensation Arrangement By Share-Based Payment Award, Fair Value Assumptions, Grant Date Fair Value Share-based Compensation Arrangement By Share-Based Payment Award, Fair Value Assumptions, Grant Date Fair Value Grant date fair value per option Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Outstanding at end of period, Shares Outstanding at beginning of period, Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period Granted, Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Forfeited, Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period Expired / Canelled, Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Exercisable at end of period, Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Outstanding at end of period, Weighted Average Exercise Price Outstanding at beginning of period, Weighted Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Granted, Weighted Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Forfeited, Weighted Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price Expired / Canelled, Weighted Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Exercised, Weighted Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Exercisable at end of period, Weighted Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Outstanding at end of period, Weighted Average Remaining Life (years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Exercisable at end of period, Weighted Average Remaining Life (years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Outstanding at end of period, Aggregate Intrinsic Value Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Exercisable at end of period, Aggregate Intrinsic Value Schedule of Defined Benefit Plans Disclosures [Table] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan, Contributions by Employer Cash contributions made by the Company Retirement Plan Type [Axis] Retirement Plan Type [Domain] Defined Benefit Plans and Other Postretirement Benefit Plans [Domain] Pension Plans Defined Benefit [Member] Pension Benefits [Member] Other Postretirement Benefit Plans Defined Benefit [Member] Other Postretirement Benefits [Member] Defined Benefit Plan, Service Cost Service cost Defined Benefit Plan, Interest Cost Interest cost Defined Benefit Plan, Expected Return on Plan Assets Expected return on plan assets Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Amortization of prior service cost Defined benefit plan amortization of actuarial loss. Defined benefit plan amortization of actuarial loss Amortization of actuarial loss Defined benefit plan settlement charge. Defined benefit plan settlement charge Settlement charge Defined Benefit Plan, Special Termination Benefit Charge Defined Benefit Plan, Special Termination Benefit Charge Special termination benefit charge Defined Benefit Plan, Net Periodic Benefit Cost Net periodic benefit cost Water And Wastewater Rates [Table] Water And Wastewater Rates [Table] Geographical [Axis] Segment Geographical [Domain] Geographical [Domain] Indiana And Ohio [Member] Indiana And Ohio [Member] Indiana And Ohio [Member] Illinois and North Carolina [Member] Illinois And North Carolina [Member] Illinois And North Carolina [Member] Water And Wastewater Rates [Line Items] Water And Wastewater Rates [Line Items] Base rate increase designed to increase total operating revenues on an annual basis Base rate increase designed to increase total operating revenues on an annual basis Infrastructure Rehabilitation Surcharges Infrastructure Rehabilitation Surcharges Infrastructure rehabilitation surcharges Taxes Other Than Income Taxes [Table] Taxes Other Than Income Taxes [Table] Statement, Scenario [Axis] Scenario Unspecified [Domain] Scenario, Unspecified [Domain] Property [Member] Property [Member] Property [Member] Gross Receipts, Excise and Franchise [Member] Gross Receipts Excise And Franchise [Member] Gross Receipts, Excise And Franchise [Member] Payroll [Member] Payroll [Member] Payroll [Member] Regulatory assessments [Member] Regulatory Assessments [Member] Regulatory Assessments [Member] Pumping Fees [Member] Pumping Fees [Member] Pumping Fees [Member] Other Taxes [Member] Other Taxes [Member] Other [Member] Taxes Other Than Income [Line Items] Taxes Other Than Income [Line Items] Schedule of Segment Reporting Information, by Segment [Table] Statement, Business Segments [Axis] Segment [Domain] Segment [Domain] Reportable Subsegments [Member] Reportable Segment [Member] Segment Reporting Information [Line Items] Number of Operating Segments Operating Segments Number of Reportable Segments Reportable Segments Interest expense, net of AFUDC which represents capitalized costs used to finance the construction of utility plants. Interest Expense Net Of Afudc Interest expense, net Loss Contingency, Estimate of Possible Loss Aggregate amount accrued for loss contingencies Estimated Insurance Recoveries Amount probable of recovery through insurance Self Insurance Reserve Insurance reserve for employee medical benefit program Income Tax Authority [Table] Income Tax Authority [Table] Income Tax Authority [Axis] Income Tax Authority [Domain] Income Tax Authority [Domain] Internal Revenue Service I R S [Member] Federal [Member] State And Local Jurisdiction [Member] State [Member] Income Taxes [Line Items] Income Taxes [Line Items] Change in Operating Loss Carryforward Change in operating loss carryforward Operating loss carryforwards Operating Loss Carryforwards, Valuation Allowance Operating loss carryforwards, valuation allowance Operating loss carryforwards, expiration beginning dates Balance at March 31 Unrecognized tax benefits Deferred Tax Assets, Operating Loss Carryforwards Deferred tax assets, operating loss carryforwards Effective Income Tax Rate, Continuing Operations Effective income tax rate Unrecognized Tax Benefits that Would Impact Effective Tax Rate Unrecognized tax benefits that would impact effective tax rate New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncement Or Change In Accounting Principle, Cumulative Effect Of Change On Gross Equity Or Net Assets New Accounting Pronouncement Or Change In Accounting Principle, Cumulative Effect Of Change On Gross Equity Or Net Assets Adjustment to retained earnings, before tax Bank Note B [Member] Bank Note B [Member] Bank notes at 1.921% due 2017 [Member] Bank Note C [Member] Bank Note C [Member] Bank notes at 1.975% due 2018 [Member] Stock Compensation Plan [Member] Stock Compensation Plan [Member] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Operating Segments [Member] Regulated [Member] Corporate And Other [Member] Other [Member] Disposal Group Classification [Axis] Disposal Group Classification [Domain] Disposal Group Classification [Domain] Disposal Group Not Discontinued Operations [Member] Disposal Group, Not Discontinued Operations [Member] Consolidated Entities [Axis] Consolidated Entities [Domain] Consolidated Entities [Domain] Aqua Illinois [Member] Aqua Illinois [Member] Aqua Illinois [Member] Debt Instrument A [Member] Debt Instrument [Member] First Mortgage Bond Maturing 2032 [Member] Debt Instrument B [Member] Debt Instrument B [Member] First Mortgage Bond Maturing 2037 [Member] Debt Instrument C [Member] Debt Instrument C [Member] First Mortgage Bond Maturing 2038 [Member] Debt Instrument D [Member] Debt Instrument D [Member] First Mortgage Bond Maturing 2047 [Member] Debt Instrument E [Member] Debt Instrument E [Member] First Mortgage Bond Maturing 2049 [Member] Debt Instrument F [Member] Debt Instrument F [Member] First Mortgage Bond Maturing 2050 [Member] Fair Value, Hierarchy [Axis] Fair Value Measurements Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Fair Value Inputs Level1 [Member] Fair Value, Inputs, Level 1 [Member] Fair Value Inputs Level2 [Member] Fair Value, Inputs, Level 2 [Member] Vesting [Axis] Vesting [Domain] Vesting [Domain] Share Based Compensation Award Tranche One [Member] Share-based Compensation Award, Tranche One [Member] Share Based Compensation Award Tranche Two [Member] Share-based Compensation Award, Tranche Two [Member] Share Based Compensation Award Tranche Three [Member] Share-based Compensation Award, Tranche Three [Member] Adjustments for New Accounting Pronouncements [Axis] Type Of Adoption [Member] Type of Adoption [Domain] Adjustments For New Accounting Principle Early Adoption [Member] Adjustments for New Accounting Principle, Early Adoption [Member]