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 Property, Plant and Equipment, Gross, Ending Balance Property, Plant and Equipment, Gross, Beginning Balance Total property, plant and equipment Less: accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Ending Balance Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Beginning Balance Less: accumulated depreciation Net property, plant and equipment Property, Plant and Equipment, Net, Ending Balance Property, Plant and Equipment, Net, Beginning Balance Property, plant and equipment, net 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 Cash and cash equivalents at end of year Cash and cash equivalents Accounts receivable and unbilled revenues, net Accounts receivable and unbilled revenues, net Tax Credit Carryforward, Amount Deferred income taxes Inventory, materials and supplies Inventory, materials and supplies Prepayments and other current assets Prepayments and other current assets Assets of Disposal Group, Including Discontinued Operation, Current Current assets Assets of discontinued operations held for sale Assets of discontinued operations held for sale Total current assets Total current assets Regulatory Assets Noncurrent Regulatory assets Deferred Costs and Other Assets Deferred charges and other assets, net Restricted Cash and Cash Equivalents, Noncurrent Funds restricted for construction activity Goodwill placeholder Balance at September 30, 2012 Balance at December 31, 2011 Goodwill Goodwill Total Assets Total assets Total assets Aqua America stockholders' equity: Common stock, $.50 par value Common stock at $.50 par value, authorized 300,000,000 shares, issued 138,449,039 and 137,148,749 in 2010 and 2009 Common Stock, Value, Issued, Ending Balance Common Stock, Value, Issued, Beginning Balance Common stock at $.50 par value, authorized 300,000,000 shares, issued 140,697,726 and 139,525,580 in 2012 and 2011 issued xxx,xxx,xxx and 138,449,039 in 2011 and 2010 Common stock, $.50 par value Additional Paid In Capital Common Stock Additional Paid in Capital, Common Stock, Ending Balance Additional Paid in Capital, Common Stock, Beginning Balance Capital in excess of par value Retained Earnings Accumulated Deficit Retained Earnings (Accumulated Deficit), Ending Balance Retained Earnings (Accumulated Deficit), Beginning Balance Retained earnings Retained earnings Treasury stock, at cost Treasury stock, at cost, 767,178 and 710,482 shares in 2012 and 2011 Treasury stock, at cost Treasury Stock, Value, Ending Balance Treasury Stock, Value, Beginning Balance Treasury stock, at cost Accumulated Other Comprehensive Income Loss Net Of Tax Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance Accumulated other comprehensive income Accumulated other comprehensive income Accumulated other comprehensive income Total Aqua America stockholders' equity Stockholders' Equity Attributable to Parent, Ending Balance Stockholders' Equity Attributable to Parent, Beginning Balance Aqua America stockholders' equity Total Aqua America stockholders' equity MinorityInterest Stockholders' Equity Attributable to Noncontrolling Interest, Ending Balance Stockholders' Equity Attributable to Noncontrolling Interest, Beginning Balance Noncontrolling interest Noncontrolling interest Total equity Balance Balance Total equity Long Term Debt Noncurrent Long-term debt, excluding current portion Long-term debt, excluding current portion Long-term debt, excluding current portion Commitments and contingencies 2009 Commitments and contingencies (See Note 13) Current liabilities: Current portion of long-term debt Current portion of long-term debt Current portion of long-term debt Current portion of long-term debt Loans payable Loans payable Accounts payable Accounts Payable, Current, Total Interest Payable, Current Accrued interest Accrued taxes Dividends Payable, Current Dividends payable Accrued Liabilities Current Other accrued liabilities Other accrued liabilities Liabilities of Disposal Group, Including Discontinued Operation, Current Current liabilities Liabilities of discontinued operations held for sale Liabilities of discontinued operations held for sale 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 Regulatory Liability, Noncurrent, Total Other Liabilities Noncurrent Other Other Total deferred credits and other liabilities Total deferred credits and other liabilities Contributions in aid of construction Non-cash property as advances or contributions Contributions in aid of construction Total liabilities and stockholders' equity Total liabilities and stockholders' equity Common stock, par value Common stock, par value Common stock, shares authorized Common stock, authorized Common stock, shares issued Common Stock, Shares Issued, Total Common stock, issued Treasury stock, shares Treasury Stock, Shares, Ending Balance Treasury Stock, Shares, Beginning Balance Treasury shares Consolidated Statements Of Net Income [Abstract] Operating revenues Operating revenues Cost and expenses: Operating expenses: Utilities Operating Expense Maintenance And Operations Operations and maintenance Operations and maintenance expense Depreciation Depreciation Amortization Amortization of the acquisition adjustments Amortization Taxes Other Than Income Taxes Taxes other than income taxes Taxes, Miscellaneous, Total Total expenses Total expenses Operating income Operating income (loss) Operating income Operating income Other expense (income): Interest expense, net Interest expense, net 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 Gain on sale of other assets Gain on sale of other assets Gain on sale of other assets Net Income (Loss) Attributable to Noncontrolling Interest, Joint Venture Partners Equity earnings in joint venture Income (Loss) from Continuing Operations before Income Taxes, Domestic Income from continuing operations before income taxes Provision for income taxes Income tax expense (benefit) Total tax expense Income tax benefit Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest Income from continuing operations Income from continuing operations Income (loss) from continuing operations Discontinued operations: Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax Income from discontinued operations before income taxes Income from discontinued operations before income taxes Discontinued Operation, Tax Effect of Discontinued Operation Discontinued Operation, Tax Effect of Discontinued Operation, Total Provision for income taxes Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest (Loss) income from discontinuing operations Income (loss) from discontinued operations (Loss) income from discontinued operations Net income attributable to common shareholders Net income Income from continuing operations Net income attributable to common shareholders Net income attributable to common shareholders Income From Continuing Operations Per Share [Abstract] Income from continuing operations per share: Income (Loss) from Continuing Operations, Per Basic Share Income from continuing operation per common share, basic Basic income from continuing operations per common share Income (Loss) from Continuing Operations, Per Outstanding Share, Total Basic Income (Loss) from Continuing Operations, Per Diluted Share Income from continuing operation per common share, diluted Diluted income from continuing operations per common share Diluted (Loss) Income From Discontinued Operations Per Share [Abstract] Loss Income From Discontinued Operations Per Share [Abstract] Income from discontinued operations per share: Income (Loss) from Discontinued Operations, Net of Tax, Per Basic Share (Loss) income from discontinuing operations per common share, basic (Loss) income from discontinuing operations, Basic Income (Loss) from Discontinued Operations, Net of Tax, Per Outstanding Share, Total Basic Income (Loss) from Discontinued Operations, Net of Tax, Per Diluted Share (Loss) income from discontinuing operations per common share, diluted (Loss) income from discontinuing operations, Diluted Income (Loss) from Discontinued Operations, Net of Tax, Per Diluted Share, Total Diluted Net Income Per Common Share [Abstract] Earnings per Share [Abstract] Net income per common share: Earnings Per Share Basic Basic net income per common share Basic Net income Basic earnings per share - Net income Earnings Per Share Diluted Diluted net income per common share Diluted Net income Diluted earnings per share - Net income 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 the period for basic computation Diluted Average common shares outstanding during the period for diluted computation Average common shares outstanding during the period for diluted computation Cash dividends declared per common share Cash dividends declared and paid Cash dividends declared per common share Dividend 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 (loss) on investments Unrealized holding (loss) gain on investments Reclassification adjustment for (gains) losses reported in net income Reclassification adjustment for gain reported in net income (3) (4) Reclassification adjustment for (gains) losses reported in net income Reclassification adjustment for gain (losses) reported in net income, net of income tax Reclassification adjustment for gains reported in net income, net of income tax Reclassification adjustment for gain reported in net income Reclassification adjustment for losses (gains) reported in net income Reclassification adjustment for gain reported in net income Comprehensive income Comprehensive income Other comprehensive income, net of income tax of $26 Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, Tax Income taxes arising from net unrealized holding gain on investments Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax Income taxes arising from reclassification adjustment for gain 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] Long Term Debt Of Subsidiaries ten point four zero percentage [Member] Long Term Debt Of Subsidiaries Ten Point Four Zero Percentage [Member] Long-Term Debt Of Subsidiaries 10.40% [Member] Notes At Three Point Five Seven Percent [Member] Notes At Three Point Five Seven Percent [Member] Notes at 3.57% due 2027 [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% [Member] Long-term debt: Debt Instrument, Principal Outstanding Debt instrument principal outstanding Long-term debt1 Long-term debt Long-term debt Other Notes Payable, Noncurrent Notes payable to bank under revolving credit agreement, variable rate, due March 2017 Notes ranging from 4.62% to 4.87%, due 2013 through 2024 Unsecured notes payable Unsecured notes payable Unsecured Debt, Total Long-term debt and capital lease obligations Total long-term debt Total long-term debt Long-term debt, including current portion Long-term debt of discontinued operations Long-Term Debt Of Discontinued Operations Less: long-term debt of discontinued operations Long-term debt of discontinued operations Long-term debt of continuing operations Long-Term Debt Of Continuing Operations Long-term debt of continuing operations Long-term debt of continuing operations Long-term debt, including current portion Total capitalization Total capitalization 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 5.01% To 5.95% [Member] Debt Instrument, Interest Rate, Stated Percentage Debt instrument, interest rate Interest rate Interest rate range, minimum Interest Rate Range, Minimum Interest rate range, maximum Interest Rate Range, Maximum Debt Instrument Maturity Date Start Debt Instrument Maturity Date Start Maturity date range, start Debt Instrument Maturity Date End Debt Instrument Maturity Date End Maturity date range, end Debt Instrument, Maturity Date, Year Debt Instrument, Maturity Date, Year Maturity date 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] Common Stock Including Additional Paid In Capital [Member] Capital 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 (Loss) [Member] Noncontrolling Interest [Member] Noncontrolling Interest [Member] Net income Net income Other Comprehensive Income (Loss), Net of Tax Other Comprehensive Income (Loss), Net of Tax, Total Other comprehensive loss net of income tax of $99 Payments Of Dividends Common Stock Dividends paid on common stock Dividends paid Dividends paid Dividends Dividends Dividends paid Dividends on common stock Dividends Common Stock Cash Declared Dividends Common Stock Cash Declared Dividends declared Dividends declared Proceeds from issuing common stock Sale of stock Sale of stock (436,861 shares) Proceeds from issuance of common stock Payments For Repurchase Of Common Stock Repurchase of common stock Repurchase of stock (30,033 shares) Repurchase of stock (62,997 shares) Repurchase of common stock Repurchase of common stock Repurchase of stock Stock granted during period, value share-based compensation Equity compensation plan (15,518 shares) Stock Granted During Period, Value, Share-based Compensation, Net of Forfeitures, Total Equity compensation plan Stock Issued During Period, Value, Stock Options Exercised Exercise of stock options (726,068 shares) Stock Issued During Period Value Share Based Compensation Stock-based compensation Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures, Total Employee stock plan tax benefits Employee stock plan tax benefits Consolidated Statement Of Equity (Parenthetical) [Abstract] Other Comprehensive Income Available For Sale Securities Tax Abstract Other Comprehensive Income (Loss), Tax Other Comprehensive Loss, Tax Other Comprehensive Loss 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, Options, Grants in Period Equity compensation plan, shares Granted, Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures, Total Equity Compensation Plan, shares Exercise Of Stock Options, Shares Exercised, Shares Exercise of stock options, shares Exercised, Shares Consolidated Statements Of Cash Flow [Abstract] Cash flows from operating activities: Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent Income (loss) from discontinued operations Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent, Total Income (Loss) from Continuing Operations Attributable to Parent Income from continuing operations Income from continuing operations Income from continuing operations Adjustments to reconcile net income to net cash flows from operating activities: Adjustments to reconcile income from continuing operations to net cash flows from operating activities: Depreciation and amortization Depreciation and amortization Deferred Income Tax Expense (Benefit), Total Deferred income taxes Total deferred income taxes Provision for doubtful accounts Share Based Compensation Stock-based compensation Stock-based compensation Gain (Loss) on Sale of Business Gain on sale of utility system Net decrease in receivables, inventory and prepayments Net increase in receivables, inventory and prepayments Net increase in receivables, inventory and prepayments Net increase in receivables, inventory and prepayments Net decrease in payables, accrued interest, accrued taxes and other accrued liabilities Net increase in payables, accrued interest, accrued taxes and other accrued liabilities Net (decrease) increase on payables, accrued interest, accrued taxes and other accrued liabilities Increase Decrease In Other Operating Assets Other Other Other Net Cash Provided by (Used in) Operating Activities, Continuing Operations Operating cash flows from continuing operations Operating cash flows from continuing operations Cash Provided by (Used in) Operating Activities, Discontinued Operations Operating cash flows (used in) from discontinued operations, net Net cash flows from operating activities Net cash flows from operating activities Net cash flows from operating activities Cash flows from investing activities: Consolidated Statements of Cash Flows Payments to acquire property, plant and equipment Property, plant and equipment additions, including allowance for funds used during construction of $3,484 and $5,689 Capital expenditures Property, plant and equipment additions, including allowance for funds used during construction of $1,940 and $3,032 Capital additions Payments to Acquire Waste Water Systems Acquisitions of utility systems and other, net Additions to funds restricted for construction activity Additions to funds restricted for construction activity Additions to funds restricted for construction activity Release of funds previously restricted for construction activity Amount of AFUDC related to equity funds 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 Proceeds from Sale and Collection of Notes Receivable Proceeds from note receivable Proceeds from Sale and Collection of Notes Receivable, Total Payments to Acquire Interest in Joint Venture Investment in joint venture Investment in joint venture Other Other Other Other Net Cash Provided by (Used in) Investing Activities, Continuing Operations Investing cash flows used in continuing operations Cash Provided by (Used in) Investing Activities, Discontinued Operations Investing cash flows (used in) discontinued operations, net Net cash flows used in investing activities Net cash flows used in investing activities Net cash flows used in investing activities Cash flows from financing activities: Customers' advances and contributions in aid of construction Repayments of customers' advances Repayments of customers' advances Net proceeds (repayments) of short-term debt Net (repayments) proceeds of short-term debt Net (repayments) proceeds of short-term debt Proceeds from long-term debt Proceeds from long-term debt Repayments of long-term debt Repayments of long-term debt Repayments of long-term debt Change in cash overdraft position Change in cash overdraft position Proceeds from stock options exercised Exercise of stock options Proceeds from exercised stock options Exercise of stock options (123,665 shares) Share-based compensation windfall tax benefits Stock-based compensation windfall tax benefits Net Cash Provided by (Used in) Financing Activities, Continuing Operations Financing cash flows from (used in) continuing operations Financing cash flows used in discontinued operations, net Financing cash flows from discontinued operations, net Net cash flows from financing activities Net cash flows from financing activities Net cash flows from (used in) financing activities Net increase in cash and cash equivalents Net decrease in cash and cash equivalents 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 Discontinued Operations And Other Dispositions [Abstract] Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Discontinued Operations And Other Dispositions Dispositions Fair Value Of Financial Instruments [Abstract] Fair Value Disclosures [Text Block] Fair Value Of Financial Instruments FairValueDisclosuresTextBlock Earnings Per Share [Text Block] Net Income Per Common Share Capitalization [Abstract] Capitalization Disclosure [Text Block] Capitalization Disclosure [Text Block] Capitalization Stock-Based Compensation [Abstract] Disclosure Of Compensation Related Costs Share Based Payments Text Block Stock-Based Compensation Employee Stock And Incentive Plan Pension Plans And Other Postretirement Benefits [Abstract] Pension And Other Postretirement Benefits Disclosure [Text Block] Pension Plans And Other Postretirement Benefits PensionAndOtherPostretirementBenefitsDisclosureTextBlock 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] Taxes Other Than Income Taxes Text Block Taxes Other Than Income Taxes Text Block Taxes Other Than Income Taxes 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] Summary Of Changes In Goodwill Schedule Of Goodwill Schedule of Purchase Price Allocation [Table Text Block] Schedule Of Purchase Price Allocation Schedule Of Disposal Groups Including Discontinued Operations Income Statement Disclosures [Table Text Block] Schedule Of Disposal Groups Including Discontinued Operations Income Statement Disclosures [Table Text Block] Summary Of Discontinued Operations Presented In Consolidated Statements Of Income And Comprehensive Income Schedule of Disposal Groups, Including Discontinued Operations, Income Statement, Balance Sheet and Additional Disclosures [Table Text Block] Schedule Of Disposal Groups Including Discontinued Operations 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 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] Stock Options [Member] Stock Options [Member] Restricted Stock [Member] Restricted Stock [Member] Schedule of Nonvested Performance-based Units Activity [Table Text Block] Summary Of Nonvested PSU Transactions Schedule of Nonvested Restricted Stock Units Activity [Table Text Block] Summary Of Nonvested RSU Transactions Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block] Summary Of Compensation Costs Schedule Of Compensation Costs For Stock-Based Compensation 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 - Restricted Stock Schedule of Net Benefit Costs [Table Text Block] Components Of Net Periodic Benefit Costs Taxes Other Than Income Taxes Table Text Block Taxes Other Than Income Taxes 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 Goodwill by segment for discontinued operations. Goodwill By Segment For Discontinued Operations Goodwill by segment for discontinued operations Schedule of Goodwill [Table] Statement, Business Segments [Axis] Segment [Domain] Segment [Domain] Regulated Segment [Member] Regulated Segment [Member] Regulated Segment [Member] Other Segment [Member] Other Segment [Member] Other Segment [Member] Goodwill [Line Items] Goodwill, Acquired During Period Goodwill acquired Goodwill acquired during year Reclassification Of Goodwill, Acquisition Adjustment Reclassification Of Goodwill, Acquisition Adjustment Reclassifications to utility plant acquisition adjustment Goodwill, Other Changes Other Other Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Axis] Business Acquisition Acquiree [Domain] Business Acquisition, Acquiree [Domain] American Water Works Company, Inc. [Member] American Water Works Company Inc [Member] American Water Works Company, Inc. [Member] Business Acquisition [Line Items] Number of customers. Number of customers Number of customers Business Acquisition, Cost of Acquired Entity, Cash Paid Cash paid for business acquisition Cash paid for acquisitions Business Acquisition, Purchase Price Allocation, Liabilities Assumed Assumed liabilities including debt Total liabilities assumed Liabilities assumed from acquisition Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment Property, plant and equipment, net Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment, Total Business Acquisition, Purchase Price Allocation, Current Assets Current assets Business Acquisition, Purchase Price Allocation, Current Assets, Total Business Acquisition, Purchase Price Allocation, Other Noncurrent Assets Other long-term assets Business Acquisition, Purchase Price Allocation, Goodwill Amount Goodwill Business Acquisition, Purchase Price Allocation, Goodwill Amount, Total Business Acquisition, Purchase Price Allocation, Assets Acquired Total assets acquired Business Acquisition, Purchase Price Allocation, Current Liabilities Current liabilities Business Acquisition, Purchase Price Allocation, Current Liabilities, Total Business Acquisition, Purchase Price Allocation, Noncurrent Liabilities, Long-term Debt Long-term debt, excluding current portion Business Acquisition, Purchase Price Allocation, Other Noncurrent Liabilities Other long-term liabilities Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net Net assets acquired Disposal Group By Location [Table] Disposal Group By Location [Table] Discontinued Operations And Other Dispositions [Line Items] Discontinued Operations And Other Dispositions [Line Items] Liabilities assumed by the purchaser from the sale of the regulated water operations. Liabilities Assumed By The Purchaser For The Sale Of Regulated Water Operations Liabilities assumed by the purchaser for the sale of regulated water operations Proceeds from Divestiture of Businesses Proceeds from sale of regulated water operations Initial valuation payment Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax Gain on sale Gain (loss) on sale Estimated loss on discontinued operations Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax, Total Gain (loss) on sale Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax Gain (loss) on sale, after tax Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax, Total Gain (loss) on sale, after tax Disposal Group, Including Discontinued Operation, Deferred Tax Liabilities Deferred tax liabilities Deferred income taxes and investment tax credits Proceeds from Sale of Property, Plant, and Equipment Proceeds from Sale of Property, Plant, and Equipment, Total Proceeds on sale of water and wastewater utility system Gain (Loss) on Sale of Property Plant Equipment Gain (Loss) on Sale of Property Plant Equipment, Total Gain on sale of water and wastewater utility system Percentage of utility system that assets represent Percentage of utility system that assets represent Percentage of utility system that assets represent initial proceeds resulting from sale of a portion of a utility system pending complete valuation. Initial Proceeds Resulting From Sale Of A Portion Of A Utility System Pending Complete Valuation Initial valuation payment Percentage of utility system that has been relinquished Percentage of utility system that has been relinquished Disposal Group, Including Discontinued Operation, Revenue Operating revenues Disposal Group, Including Discontinued Operation, Operating Expense Total operating expenses Disposal Group, Including Discontinued Operation, Operating Income (Loss) Operating income Operating income Amount of gain, before tax expense or benefit and not previously recognized, resulting from the sale of a business component. Discontinued Operation, Gain From Disposal Of Discontinued Operation, Before Income Tax Gain on sale Gain on sale Amount of loss, before tax expense or benefit and not previously recognized, resulting from the sale of a business component. Discontinued Operation, Loss From Disposal Of Discontinued Operation, Before Income Tax Loss on sale Disposal group including discontinued operation operating other expense net Disposal Group Including Discontinued Operation Operating Other Expense Net Other expense, net Disposal group including discontinued operation property, plant and equipment, gross Disposal Group Including Discontinued Operation Property, plant and equipment, Gross Property, plant and equipment, at cost Disposal group including discontinued operation accumulated depreciation Disposal Group Including Discontinued Operation Accumulated Depreciation Less: accumulated depreciation Disposal Group, Including Discontinued Operation, Property, Plant, and Equipment, Net Less discontinued operations Less discontinued operations Net property, plant and equipment Disposal group including discontinued operation current assets Disposal Group Including Discontinued Operation Current Assets Current assets Disposal group including discontinued operation regulatory assets Disposal Group Including Discontinued Operation Regulatory assets Regulatory assets Disposal Group, Including Discontinued Operation, Goodwill Goodwill Disposal Group, Including Discontinued Operation, Other Noncurrent Assets Other assets Disposal group including discontinued operation long-term debt, excluding current portion Disposal Group Including Discontinued Operation Long-Term Debt, Excluding Current Portion Long-term debt, excluding current portion Disposal group including discontinued operation current liabilities Disposal Group Including Discontinued Operation Current Liabilities Current liabilities Disposal group including discontinued operation deferred income taxes and investment tax credits Disposal Group Including Discontinued Operation Deferred Income Taxes And Investment Tax Credits Deferred income taxes and investment tax credits Disposal group including discontinued operation contributions in aid of construction Disposal Group Including Discontinued Operation Contributions In Aid Of Construction Contributions in aid of construction Disposal Group, Including Discontinued Operation, Other Noncurrent Liabilities Other liabilities Disposal group including discontinued operation net assets Disposal Group Including Discontinued Operation Net Assets Net assets Net assets Long Term Debt Discontinued Operations Long Term Debt Discontinued Operations Long-term debt discontinued operations Debt Instrument, Fair Value Disclosure Fair value of long-term debt for discontinued operations Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping, Disclosure Item Amounts [Axis] Fair Value [Domain] Fair Value [Domain] Fair Value [Domain] Carrying Reported Amount Fair Value Disclosure [Member] Carrying Amount [Member] Estimate Of Fair Value Fair Value Disclosure [Member] Estimated Fair Value [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Long Term Debt Fair Value Long-term debt Incremental Common Shares Attributable to Share-based Payment Arrangements Dilutive effect of employee stock-based compensation Incremental Common Shares Attributable to Share-based Payment Arrangements, Total Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Employee stock options excluded from calculations of diluted net income per share Schedule of Long-term Debt Instruments [Table] Statement, Scenario [Axis] Scenario Unspecified [Domain] Scenario, Unspecified [Domain] Scenario Previously Reported [Member] Scenario, Previously Reported [Member] Capitalization [Line Items] Debt Instrument, Face Amount Debt instrument, issued Debt Instrument, Maturity Date, Description Debt instrument, maturity date Noncash or Part Noncash Acquisition, Debt Assumed Assumed long-term debt Liabilities, Fair Value Adjustment Fair value adjustment to assumed long-term debt Line of Credit Facility, Maximum Borrowing Capacity Debt instrument, face amount Debt Instrument, Maturity Debt Instrument, Maturity Debt instrument, term length Number Of Banks Number Of Banks Number of banks Debt Instrument Daily Loans Sublimit Face Amount Debt Instrument Daily Loans Sublimit Face Amount Debt instrument daily loans sublimit face amount Potential future sale of common stock, preferred stock, debt securities, and other securities Potential future sale of common stock, preferred stock, debt securities, and other securities Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Two Thousand Nine Omnibus Equity Compensation Plan [Member] Two Thousand Nine Omnibus Equity Compensation Plan [Member] 2009 Plan [Member] Range [Axis] Range [Member] Range [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Underlying stock option and restricted stock awards Shares authorized Number of shares authorized for issuance Share based compensation arrangement by share based payment award maximum percentage of shares available for issuance may be issued as restricted stock Share Based Compensation Arrangement By Share Based Payment Award Maximum Percentage Of Shares Available For Issuance May Be Issued As Restricted Stock Maximum percentage of shares available for issuance may be issued as restricted stock Share-based Compensation Arrangement by Share-based Payment Award, Maximum Shares Per Employee Maximum shares subject to grants to any one individual per year 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 Excess Tax Benefit from Share-based Compensation, Operating Activities Tax benefit associated witth stock-compensation that vested or was excercised Performance Period Specified In Grant Performance Period Specified In Grant Performance period specified in grant, in years Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Vesting period for PSU grants Vesting period, in years 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 Weighted-average fair value at the date of grant for PSUs Granted, Weighted Average Fair Value Weighted average fair value of restricted 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, Grants in Period Granted, 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 Forfeited, Number of Share Units Forfeited, Number of Share Units Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Vested, Number of Share Units Vested, number of shares Vested, Number of Share Units Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period Share unit awards 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 Vested, 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 unit awards issued, Weighted Average Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost Stock-based compensation for stock options within operations and maintenance expenses Allocated Share-based Compensation Expense, Total Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Stock-based compensation Stock-based compensation Income tax benefit Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Outstanding at end of period, Shares Outstanding at beginning of period, Shares Outstanding at end of period, shares Outstanding, beginning of year Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Forfeited, Shares Forfeited, Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period Expired, Shares Expired, 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 Outstanding at end 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, 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 Exercisable at end of period, shares 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) Outstanding, end of year, Weighted Average Remaining Life (years) 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) 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 Outstanding at beginning of period, Weighted Average Remaining Life (years) 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 Exercisable at end of period, Aggregate Intrinsic Value Schedule of Defined Benefit Plans Disclosures [Table] Scenario Forecast [Member] Scenario, Forecast [Member] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Axis] Defined Benefit Plans [Domain] Defined Benefit Plans and Other Postretirement Benefit Plans [Domain] Other Postretirement Benefit Plans Defined Benefit [Member] Other Postretirement Benefits [Member] Defined Benefit Pension Plans [Member] Defined Benefit Pension Plans [Member] Defined Benefit Pension Plans [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan, Contributions by Employer Cash contributions made by the Company Employer contributions Pension Plans Defined Benefit [Member] Pension 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 Expected return on plan assets Defined Benefit Plan, Amortization of Transition Obligations (Assets) Amortization of transition obligation 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 amortization of regulatory assets. Defined benefit plan amortization of regulatory assets Amortization of regulatory asset Defined benefit plan capitalized cost. Defined Benefit Plan Capitalized Cost Capitalized costs Capitalized costs Defined benefit plan settlement charge. Defined benefit plan settlement charge Settlement charge Defined benefit plan curtailment charge Defined Benefit Plan Curtailment Charge Curtailment (credit) charge Defined Benefit Plan Net Periodic Benefit Cost Including Discontinued Operations Defined Benefit Plan Net Periodic Benefit Cost Including Discontinued Operations Net periodic benefit cost including discontinued operations Net periodic benefit cost including discontinued operations Net periodic benefit costs for discontinued operation Net Periodic Benefit Costs For Discontinued Operation Less discontinued operations Net periodic benefit costs for discontinued operation Defined Benefit Plan, Net Periodic Benefit Cost Net periodic benefit cost Net periodic benefit cost Legal Entity [Axis] Entity [Domain] Entity [Domain] Pennsylvania operating division [Member] Pennsylvania Operating Division [Member] Pennsylvania Operating Division [Member] Other Subsidiaries [Member] Other Subsidiaries [Member] Other Subsidiaries [Member] Water And Wastewater Rates [Line Items] Water And Wastewater Rates [Line Items] Authorized increase in revenue from utility service on an annualized basis. Authorized increase in revenue from utility service Authorized increase in revenue Distribution System Improvement Charges Distribution System Improvement Charges Distribution system improvement charges Distribution System Improvement Charges Percent Over Base Rate Distribution System Improvement Charges Percent Over Base Rate Distribution system improvement charges over base rate 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 Distribution System Improvement Charges Reset Level Upon New Base Rates Distribution System Improvement Charges Reset Level Upon New Base Rates Distribution system improvement charges reset level upon new base rates Infrastructure Rehabilitation Surcharges Infrastructure Rehabilitation Surcharges Infrastructure rehabilitation surcharges Infrastructure rehabilitation surcharges capped percentage Infrastructure Rehabilitation Surcharges Capped Percentage Infrastructure rehabilitation surcharges, capped percentage Infrastructure Rehabilitation Surcharge Percentage, Reset Level Upon New Base Rates Infrastructure Rehabilitation Surcharge Percentage, Reset Level Upon New Base Rates Infrastructure rehabilitation surcharge percentage, reset level upon new base rates Operating Divisions To Bill Interim Rates Operating Divisions To Bill Interim Rates Operating divisions to bill interim rates with authorization from the Texas Commission on Environmental Quality Billed Revenue Subject To Refund Billed Revenue Subject To Refund Billed revenue subject to refund based on the outcome of the Texas Commission on Environmental Quality Reserve For Billed Revenue Subject To Refund Reserve For Billed Revenue Subject To Refund Reserve for billed revenue subject to refund based on the outcome of the Texas Commission on Environmental Quality Taxes Other Than Income Taxes [Table] Taxes Other Than Income Taxes [Table] Taxes Other Than Income Taxes [Axis] Taxes Other Than Income Taxes [Axis] Taxes [Domain] Taxes [Domain] Taxes [Domain] Property [Member] Property [Member] Property [Member] Capital Stock [Member] Capital Stock [Member] Capital Stock [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] Other Credit Derivatives [Member] Other [Member] Taxes Other Than Income Taxes [Line Items] Taxes Other Than Income Taxes [Line Items] Taxes other than income before discontinued operations Taxes Other Than Income Before Discontinued Operations Taxes other than income before discontinued operations Taxes other than income before discontinued operations Taxes other than income taxes for discontinued operations. Taxes Other Than Income Taxes For Discontinued Operations Less discontinued operations Less discontinued operations Taxes other than income taxes for discontinued operation Total Taxes Other Than Income Taxes From Continuing Operations Total Taxes Other Than Income Taxes From Continuing Operations Total taxes other than income Total taxes other than income Schedule of Segment Reporting Information, by Segment [Table] Segment Reporting Information [Line Items] Number of Operating Segments Operating Segments Number of Reportable Segments Reportable Segments Regulated Operation [Member] Regulated [Member] Other Reporting Segment [Member] Other Reporting Segment [Member] Other [Member] Interest expense, net of AFUDC which represents capitalized costs used to finance the construction of utility plants. Interest expense, net of AFUDC Intersegment Elimination [Member] Other And Eliminations [Member] Loss Contingency, Estimate of Possible Loss Aggregate amount accrued for loss contingencies Estimated Insurance Recoveries Amount probable of recovery through insurance 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] Deferred tax assets operating loss carry forwards domestic, utilized Deferred tax assets operating loss carry forwards domestic, utilized Deferred tax assets operating loss carry forwards state and local, utilized Deferred tax assets operating loss carry forwards state and local, utilized Operating loss carryforwards Operating Loss Carryforwards, Total Operating Loss Carryforwards, Valuation Allowance Operating Loss Carryforwards, Valuation Allowance, Total Operating loss carryforwards, valuation allowance Operating loss carryforwards, expiration beginning dates Disposal Group By Location [Axis] Disposal Group By Location [Axis] Disposal Group By Location [Domain] Disposal Group By Location [Domain] Disposal Group By Location [Domain] M [E] Maine [Member] N [Y] New York [Member] F [L] Florida [Member] N [C] North Carolina [Member] M [O] Missouri [Member] T [X] Texas [Member] Long-term Debt, Type [Axis] Longterm Debt Type [Domain] Long-term Debt, Type [Domain] Senior Unsecured Notes [Member] Senior Unsecured Notes [Member] Senior Unsecured Notes [Member] Reportable Segments [Member] Reportable Segment [Member] Not Quantitatively Significant [Member] Not Quantitatively Significant [Member] Not Quantitatively Significant [Member]