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Combination [Domain] Future minimum sublease rentals, thereafter Lessee, Operating Lease, Liability, to be Paid, after Year Four Lessee, Operating Lease, Liability, to be Paid, after Year Four Letter of Credit Letter of Credit [Member] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Antidilutive securities excluded from computation of earnings per share, less than (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Entity Central Index Key Entity Central Index Key Nexus Water Group Inc. Nexus Water Group Inc. [Member] Nexus Water Group Inc. 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Plan, Amortization of Prior Service Cost (Credit) Operating Segments Operating Segments [Member] Unrealized gain (loss) on available-for-sale fixed-income securities, net of tax of $0 for the three months ended June 30, 2026 and 2025, and $0 and $(1) for the six months ended June 30, 2026 and 2025, respectively OCI, Debt Securities, Available-for-Sale, Gain (Loss), before Adjustment, after Tax Interest expense Interest expense Interest Expense, Nonoperating Total assets Fair Value, Net Asset (Liability) Gross Unrealized Gains Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax Total liabilities assumed Business Combination, Recognized Liability Assumed, Liability Treasury lock agreements, Designated as Hedging Instrument, Terminated, Transaction 1 Treasury lock agreements, Designated as Hedging Instrument, Terminated, Transaction 1 [Member] Treasury lock agreements, Designated as Hedging Instrument, Terminated, Transaction 1 Other comprehensive (loss) income before reclassifications OCI, before Reclassifications, Net of Tax, Attributable to Parent PEO PEO [Member] Settlements of long-term debt Settlements Of Long Term Debt Settlements Of Long Term Debt Cash and Cash Equivalents Cash and Cash Equivalents [Domain] Effect of dilutive forward sale agreements (in shares) Incremental Common Shares Attributable to Dilutive Effect of Equity Forward Agreements Fair Value Measurement Measurement Basis [Axis] Location, Statement of Financial Position, Activity, Capitalization Location, Statement of Financial Position, Activity, Capitalization [Axis] Other Other Liabilities, Noncurrent Goodwill Goodwill Retirement Plan Type Retirement Plan Type [Axis] Fixed-income securities Available-for-sale fixed-income securities Fixed Income Securities [Member] Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Number of business combination and asset acquisition acquired Number Of Acquisitions Accounted For As Business Combination Number Of Business Combination and Asset Acquisition Acquired Secured seller promissory note from the sale of the Homeowner Services Group Financing Receivable, after Allowance for Credit Loss, Noncurrent Accounts payable and accrued liabilities Business Combination, Recognized Liability Assumed, Accounts Payable, Current Subsequent Event Type Subsequent Event Type [Domain] Retained Earnings Retained Earnings [Member] Operating lease liabilities Operating Lease, Liability, Noncurrent Accrued taxes Taxes Payable, Current Total operating expenses, net Operating Expenses Money market and other Money Market Funds [Member] Total regulatory liabilities Litigation Settlement, Amount Awarded From Other Party, Escrow, Total Regulatory Liabilities Litigation Settlement, Amount Awarded From Other Party, Escrow, Total Regulatory Liabilities Revolving Credit Facility Revolving Credit Facility [Member] Gain (Loss) on Fixed-Income Securities AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Parent [Member] Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Amortization of Actuarial Loss Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Award Timing Disclosures [Line Items] Schedule of Carrying Amounts and Fair Values of Financial Instruments Fair Value, by Balance Sheet Grouping [Table Text Block] Net income attributable to common shareholders (in dollars per share) Earnings Per Share, Diluted Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] General rate case authorizations, annualized incremental revenues, including reduction for the amortization of the excess accumulated deferred income taxes Public Utilities, General Rate Case Authorizations, Annualized Incremental Revenues, Including Reduction For The Amortization of the Excess Accumulated Deferred Income Taxes Public Utilities, General Rate Case Authorizations, Annualized Incremental Revenues, Including Reduction For The Amortization of the Excess Accumulated Deferred Income Taxes Entity Current Reporting Status Entity Current Reporting Status Net cash provided by financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Total Shareholder Return Amount Total Shareholder Return Amount Forward Sale Agreements Forward Sale Agreements [Member] Forward Sale Agreements Payments, year one Lessee, Operating and Financing Lease, Liability, Payments, Due Year One Lessee, Operating and Financing Lease, Liability, Payments, Due Year One Number of customers who completed claim process Number of Customers Who Completed Claim Process Number of Customers Who Completed Claim Process Net short-term (repayments) borrowings with original maturities less than three months Proceeds from (Repayments of) Short-Term Debt, Maturing in Three Months or Less General rate case authorizations, annualized incremental revenues, approved amount, increase in capital investments Public Utilities, General Rate Case Authorizations, Annualized Incremental Revenues, Approved Amount, Increase (Decrease) In Capital Investments Public Utilities, General Rate Case Authorizations, Annualized Incremental Revenues, Approved Amount, Increase (Decrease) In Capital Investments Operation and maintenance Utilities Operating Expense, Maintenance and Operations Adjustments to reconcile to net cash flows provided by operating activities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Municipalities and Commercial Municipalities and Commercial [Member] Municipalities and Commercial [Member] Amounts written off Accounts Receivable, Allowance for Credit Loss, Writeoff Increase on interest on unrecognized tax benefits Unrecognized Tax Benefits, Increase (Decrease) In Interest Unrecognized Tax Benefits, Increase (Decrease) In Interest Total identifiable assets Business Combination, Recognized Asset Acquired, Asset Revenues from Contracts with Customers Revenue from Contract with Customer, Excluding Assessed Tax Remaining availability Line of Credit Facility, Remaining Borrowing Capacity Interest cost Defined Benefit Plan, Interest Cost Payments, year two Lessee, Operating and Financing Lease, Liability, Payments, Due Year Two Lessee, Operating and Financing Lease, Liability, Payments, Due Year Two Financial Instruments Financial Instruments [Domain] Non-operating benefit costs, net Benefit Costs, Non-Operating, Net Benefit Costs, Non-Operating, Net Senior Note 4.625% Due 2029 Senior Note 4.625% Due 2029 [Member] Senior Note 4.625% Due 2029 Mark-to-market derivative asset Derivative Asset Preferred stock with mandatory redemption requirements, carrying amount Preferred Stocks With Mandatory Redemption Requirements Carrying Amount Preferred Stocks With Mandatory Redemption Requirements Carrying Amount Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Underlying Securities Award Underlying Securities Amount Schedule of New Accounting Pronouncements and Changes in Accounting Principles Accounting Standards Update and Change in Accounting Principle [Table Text Block] Fair Value Estimate of Fair Value Measurement [Member] Revenue Recognition Revenue from Contract with Customer [Text Block] Natural gas outage inconvenience per household, average amount paid Loss Contingency, Natural Gas Outage Inconvenience Per Household, Average Amount Paid Loss Contingency, Natural Gas Outage Inconvenience Per Household, Average Amount Paid Authorization, Effective Date Public Utility, Authorization, Effective Date [Domain] Public Utility, Authorization, Effective Date [Domain] Secured Seller Promissory Note Secured Seller Promissory Note [Member] Secured Seller Promissory Note Operating lease, weighted-average discount rate Operating Lease, Weighted Average Discount Rate, Percent Public and other Public and Other [Member] Public and Other [Member] Segment Reporting [Table] Segment Reporting [Table] Expected contributions, remainder of fiscal year Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year Derivative, number of instruments held Derivative, Number of Instruments Held Sale of Stock [Axis] Sale of Stock [Axis] CASH FLOWS FROM INVESTING ACTIVITIES Cash Provided by (Used in) Investing Activity, Continuing Operation [Abstract] Other Other Assets, Current CASH FLOWS FROM OPERATING ACTIVITIES Cash Provided by (Used in) Operating Activity, Continuing Operation [Abstract] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] All Trading Arrangements All Trading Arrangements [Member] Other Performance Measure, Amount Other Performance Measure, Amount Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Operating income Operating Income (Loss) Estimate of the future contribution Loss Contingency, Estimate Of The Future Contribution Loss Contingency, Estimate Of The Future Contribution Revenue, remaining performance obligation Revenue, Remaining Performance Obligation, Amount Current Fiscal Year End Date Current Fiscal Year End Date Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Commitments And Contingencies [Table] Commitments And Contingencies [Table] Commitments and contingencies. Year 2027 Public Utility Authorization Effective Date January 1, 2027 [Member] Public Utility Authorization Effective Date January 1, 2027 Vehicles Vehicles [Member] Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Dividends declared per common share (in dollars per share) Dividends declared per common share (in dollars per share) Common Stock, Dividends, Per Share, Declared Entity File Number Entity File Number Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Service cost Defined Benefit Plan, Service Cost Common stock issuances Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture Schedule of Investments Classified by Contractual Maturity Date Investments Classified by Contractual Maturity Date [Table Text Block] Real Property Land, Buildings and Improvements [Member] Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Year 2025 Public Utility, Authorization, Effective Date, Year 2025 [Member] Public Utility, Authorization, Effective Date, Year 2025 Common stock, shares issued (in shares) Beginning balance (in shares) Ending balance (in shares) Common Stock, Shares, Issued Measure: Measure [Axis] Lessee, finance lease, term of contract Lessee, Finance Lease, Term of Contract Treasury stock, shares (in shares) Beginning balance (in shares) Ending balance (in shares) Treasury Stock, Common, Shares Removal costs from property, plant and equipment retirements, net Payments for (Proceeds from) Removal Costs Equity Components Equity Components [Axis] Number of new subsurface slant wells Number Of Subsurface Slant Wells Number Of Subsurface Slant Wells Products and Services Product and Service [Domain] Contributions in aid of construction Contributions in Aid of Construction California, Attrition Increase California CALIFORNIA Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Homeowner Services Group Homeowner Services Group [Member] Homeowner Services Group Capitalization: Capitalization, Long-Term Debt and Equity [Abstract] Entity Interactive Data Current Entity Interactive Data Current Number of customers serving Number of Customer Serving Number of Customer Serving Authorization, Effective Date Public Utility, Authorization, Effective Date [Axis] Public Utility, Authorization, Effective Date Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Entity Small Business Entity Small Business Comprehensive income attributable to common shareholders Comprehensive Income (Loss), Net of Tax, Attributable to Parent Future minimum sublease rentals, year three Lessee, Operating Lease, Liability, to be Paid, Year Three Termination Date Trading Arrangement Termination Date Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Other Other Liabilities, Current Exchangeable Notes Exchangeable Notes [Member] Exchangeable Notes Other Other Assets, Noncurrent CASH FLOWS FROM FINANCING ACTIVITIES Cash Provided by (Used in) Financing Activity, Continuing Operation [Abstract] Document Type Document Type Acquisitions, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Accrued liabilities Accrued Liabilities, Current Fair Value as of Grant Date Award Grant Date Fair Value Settlement payments received Litigation Settlement, Amount Awarded from Other Party Number of pending lawsuits with answers provided for Loss Contingency, Pending Claims, Number of Answers Provided For Loss Contingency, Pending Claims, Number of Answers Provided For Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Arrangement Duration Trading Arrangement Duration Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Number of approved applications Litigation Settlement, Amount Awarded from Other Party, Benefit To Customer, Regulatory Approval, Number Of Approved Applications Litigation Settlement, Amount Awarded from Other Party, Benefit To Customer, Regulatory Approval, Number Of Approved Applications Proceeds from long-term debt, net of discount Proceeds from Issuance of Long-Term Debt Deferred income taxes and investment tax credits Deferred Tax Liabilities and Investment Tax Credits, Noncurrent Deferred Tax Liabilities and Investment Tax Credits, Noncurrent Local Phone Number Local Phone Number Contract liability, noncurrent Contract with Customer, Liability, Noncurrent Other Benefits Other Postretirement Benefits Plan [Member] Consolidation Items Consolidation Items [Axis] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Registrant Name Entity Registrant Name Stockholders Equity [Line items] Stockholders Equity [Line Items] Stockholders Equity Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Defined benefit pension plan actuarial loss, tax Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, Tax Commitments and contingencies (See Note 11) Commitments and Contingencies Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Public Utility, Authorization, Effective Date, Year 2027 Public Utility, Authorization, Effective Date, Year 2027 [Member] Public Utility, Authorization, Effective Date, Year 2027 Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] New Accounting Pronouncements or Change in Accounting Principle [Table] Accounting Standards Update and Change in Accounting Principle [Table] Accounts payable and accrued liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Interest income Interest income Interest income Interest Income, Nonoperating Interest Income, Nonoperating Executive Category: Executive Category [Axis] WVAWC West Virginia American Water Company [Member] West Virginia-American water company. CAPITALIZATION AND LIABILITIES Liabilities and Equity [Abstract] Cost cap for proposed facilities, final Loss Contingency, Cost Cap For Proposed Facilities Loss Contingency, Cost Cap For Proposed Facilities Schedule of Fair Value Measurements of Assets and Liabilities on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] All Award Types Award Type [Domain] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Future minimum sublease rentals, remainder of fiscal year Lessee, Operating Lease, Liability, to be Paid, Remainder of Fiscal Year Fair Value of Financial Information Fair Value Disclosures [Text Block] Level 3 Fair Value, Inputs, Level 3 [Member] Approved cost estimates Public Utility, Approved Cost Estimates Public Utility, Approved Cost Estimates Total regulatory and other long-term assets Regulated Entity, Other Assets, Noncurrent Operating lease, term of contract Lessee, Operating Lease, Term of Contract PEO Name PEO Name Geographical Geographical [Axis] Gain (Loss) on Cash Flow Hedges Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member] Schedule of Short-term Debt [Table] Short-Term Debt [Table] Other segment items Segment Reporting, Other Segment Item, Amount Property, Plant and Equipment, Type Long-Lived Asset, Class [Axis] Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Forward Sale Agreements Equity Unit Purchase Agreements [Member] Entity Tax Identification Number Entity Tax Identification Number Senior Note 5.200% Due 2036 Senior Note 5.200% Due 2036 [Member] Senior Note 5.200% Due 2036 Legal Entity Legal Entity [Axis] Accounts Receivable, Allowance for Credit Loss [Roll Forward] Accounts Receivable, Allowance for Credit Loss [Roll Forward] Identifiable assets: Business Combination, Recognized Asset Acquired, Asset [Abstract] Unrealized (loss) gain on cash flow hedges, net of tax of $(1) and $1 for the three months ended June 30, 2026 and 2025, respectively, and $0 and $(2) for the six months ended June 30, 2026 and 2025, respectively Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax Lessee, Lease, Description [Table] Lessee, Lease, Description [Table] Cash, cash equivalents and restricted funds at beginning of period Cash, cash equivalents and restricted funds at end of period Cash, cash equivalents and restricted funds as presented on the Consolidated Statements of Cash Flows Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Acquisitions via treasury stock Stock Issued During Period, Value, Treasury Stock Reissued Regulatory Matters Regulatory Matters [Text Block] Regulatory Matters Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Number of recommended operational improvements Loss Contingency, Number of Recommended Operational Improvements Loss Contingency, Number of Recommended Operational Improvements Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Non-NEOs Non-NEOs [Member] Restricted funds Restricted funds Restricted Cash and Cash Equivalent, Current Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Debt Instrument Debt Instrument [Axis] General taxes Utilities Operating Expense, Taxes Dividends (declared per common share) Dividends, Cash Schedule of Annualized Incremental Revenues Schedule of Annualized Incremental Revenues [Table Text Block] Schedule of Annualized Incremental Revenues Contributions in aid of construction Business Combination, Recognized Liability Assumed, Contributions in Aid of Construction Business Combination, Recognized Liability Assumed, Contributions in Aid of Construction Alternative revenue programs Alternative Revenue Programs Alternative Revenue Programs Allowance for Uncollectible Accounts Credit Loss, Financial Instrument [Policy Text Block] Disposal Group Name Disposal Group Name [Axis] Customer Customer [Domain] Leases Lessee, Operating Leases [Text Block] Long-term Debt, Type Long-Term Debt, Type [Domain] Infrastructure surcharge, annualized incremental revenues, authorized amount Infrastructure surcharge, annualized incremental revenues, requested amount Public Utilities, Infrastructure Surcharge, Annualized Incremental Revenues, Requested Amount Public Utilities, Infrastructure Surcharge, Annualized Incremental Revenues, Requested Amount Net income attributable to common shareholders (in dollars per share) Earnings Per Share, Basic Advances for construction Advances for Construction Advances for Construction Contract liability, current Contract with Customer, Liability, Current Total current assets Assets, Current Range Statistical Measurement [Axis] Insider Trading Arrangements [Line Items] U.S. Government U.S. Government [Member] U.S. Government [Member] Award Type Award Type [Axis] Debt issuance costs Payments of Financing Costs Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Number of agreements, void Loss Contingency, Number of Agreements, Void Loss Contingency, Number of Agreements, Void Accounts receivable, net of allowance for uncollectible accounts of $65 and $58, respectively Accounts Receivable, after Allowance for Credit Loss, Current Retained earnings Retained Earnings (Accumulated Deficit) General rate case authorizations, annualized incremental revenues, approved amount Public Utilities, General Rate Case Authorizations, Annualized Incremental Revenues, Approved Amount Public Utilities, General Rate Case Authorizations, Annualized Incremental Revenues, Approved Amount Products and Services Product and Service [Axis] Long-term restricted funds Restricted Cash, Noncurrent Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Real Estate, Type of Property Real Estate, Type of Property [Axis] Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Deferred compensation obligations Obligations, Fair Value Disclosure Pension Benefits Pension Plan [Member] Short-term Debt [Line Items] Short-Term Debt [Line Items] Common Stock Common Stock [Member] Various Debt Maturing in 2029 Through 2061 Various Debt Maturing in 2026 Through 2061 [Member] Various Debt Maturing in 2026 Through 2061 Fair Value Total Debt Securities, Available-for-Sale Portion at Fair Value Measurement Fair Value Measurement [Domain] Residential Residential [Member] Residential [Member] Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Potential condemnation, asset value Potential Condemnation, Asset Value Potential Condemnation, Asset Value Cover [Abstract] Cover [Abstract] Number of remains pending Litigation Settlement, Amount Awarded from Other Party, Benefit To Customer, Regulatory Approval, Number Of Remains Pending Litigation Settlement, Amount Awarded from Other Party, Benefit To Customer, Regulatory Approval, Number Of Remains Pending Imputed interest Lessee, Operating and Financing Lease, Liability, Undiscounted Excess Amount Lessee, Operating and Financing Lease, Liability, Undiscounted Excess Amount Deposits Deposit Assets, Fair Value Disclosure Deposit Assets, Fair Value Disclosure Regulatory assets Business Combination, Recognized Asset Acquired, Regulatory Assets Business Combination, Recognized Asset Acquired, Regulatory Assets Derivative Contract Derivative Contract [Domain] Potential condemnation, parcels of land Potential Condemnation, Parcels of Land Potential Condemnation, Parcels of Land Public Utilities General Disclosures Public Utilities General Disclosures [Table] Equity Awards Adjustments Equity Awards Adjustments [Member] Total capitalization and liabilities Liabilities and Equity Water Services Water Services [Member] Water Services [Member] Outstanding debt Outstanding debt Commercial Paper, Outstanding Commercial Paper, Outstanding Employee Stock Option Share-Based Payment Arrangement, Option [Member] Essential Utilities, Inc. Essential Utilities, Inc. [Member] Essential Utilities, Inc. Segments Segments [Axis] Public Utility, Authorization, Effective Date, Year 2029 Public Utility, Authorization, Effective Date, Year 2029 [Member] Public Utility, Authorization, Effective Date, Year 2029 Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] American Water Capital Corp. American Water Capital Corp A W C C [Member] American Water Capital Corp AWCC. Tabular List, Table Tabular List [Table Text Block] Operating and Maintenance Agreement Operating and Maintenance Agreement [Member] Operating and Maintenance Agreement [Member] Restricted funds included in other long-term assets Restricted Cash and Cash Equivalent, Noncurrent Number of customers for whom a precautionary boil water advisory was issued to Number Of Customers For Whom A Precautionary Boil Water Advisory Was Issued To Number Of Customers For Whom A Precautionary Boil Water Advisory Was Issued To Other, net Other Nonoperating Income (Expense) Long-Term Debt Long-Term Debt [Text Block] Income tax receivable Income Taxes Receivable, Current Name Awards Close in Time to MNPI Disclosures, Individual Name Debt ratio, percentage Public Utilities, Debt Ratio Percentage Public Utilities, Debt Ratio Percentage Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] General rate case authorizations, annualized incremental revenues, requested rate increase, amount Public Utilities, General Rate Case Authorizations, Annualized Incremental Revenues, Requested Rate Increase (Decrease), Amount Public Utilities, General Rate Case Authorizations, Annualized Incremental Revenues, Requested Rate Increase (Decrease), Amount Property, Plant and Equipment, Type Long-Lived Asset, Class [Domain] Sale of stock, price per share (in dollars per share) Sale of Stock, Price Per Share Materials and supplies Inventory, Raw Materials and Supplies, Gross Total availability Commercial Paper and Line of Credit Facility, Maximum Borrowing Capacity Commercial Paper and Line of Credit Facility, Maximum Borrowing Capacity Utility Plant Utility Plant [Member] Utility plant. Adjustment to Compensation: Adjustment to Compensation [Axis] Stockholders Equity [Table] Stockholders Equity [Table] Stockholders Equity Number of pending lawsuits Loss Contingency, Pending Claims, Number Hedging Designation Hedging Designation [Domain] Merger related costs Payments for Merger Related Costs Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Hedging Designation Hedging Designation [Axis] Credit Facility Credit Facility [Axis] Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Total assets Assets, Fair Value Disclosure Long-term debt Long-Term Debt and Lease Obligation Indiana INDIANA Name Measure Name Illinois ILLINOIS Income Taxes Income Tax Disclosure [Text Block] Accounts payable Accounts Payable, Current Pay vs Performance Disclosure [Line Items] Fair Value Hierarchy Fair Value Hierarchy and NAV [Domain] Other non-cash, net Other Noncash Income (Expense) Debt Instrument [Line Items] Debt Instrument [Line Items] Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Retirement Plan Type Retirement Plan Type [Domain] Paid-in-Capital Additional Paid-in Capital [Member] Entity Filer Category Entity Filer Category Equipment Equipment [Member] Number of acquisitions Number of Assets Acquired from Business Combination and Asset Acquisition Number of Assets Acquired from Business Combination and Asset Acquisition Name Trading Arrangement, Individual Name Cash and cash equivalents Cash and Cash Equivalents Cash and Cash Equivalent General rate case authorizations, annualized incremental revenues, previously approved infrastructure filings amount Public Utilities, General Rate Case Authorizations, Annualized Incremental Revenues, Previously Approved Infrastructure Filings Amount Public Utilities, General Rate Case Authorizations, Annualized Incremental Revenues, Previously Approved Infrastructure Filings Amount Operating lease, expense Operating Lease, Expense Company Selected Measure Amount Company Selected Measure Amount Short-Term Debt Short-Term Debt [Text Block] Depreciation and amortization Depreciation, Depletion and Amortization Other investments Other Investments, Fair Value Disclosure Other Investments, Fair Value Disclosure Mountaineer Gas Company and WVAWC Mountaineer Gas Company and West Virginia American Water Company [Member] Mountaineer Gas Company and West Virginia American Water Company Loss contingency, estimated reasonably possible loss, amount Loss Contingency, Estimated Reasonably Possible Loss, Amount Loss Contingency, Estimated Reasonably Possible Loss, Amount Common stock issuances (in shares) Shares Issued, Shares, Share-Based Payment Arrangement, after Forfeiture Redeemable preferred stock at redemption value Preferred Stock, Redemption Amount Current assets: Assets, Current [Abstract] Operating lease, weighted-average remaining lease term Operating Lease, Weighted Average Remaining Lease Term Treasury lock agreements, Designated as Hedging Instrument, Terminated Treasury lock agreements, Designated as Hedging Instrument, Terminated [Member] Treasury lock agreements, Designated as Hedging Instrument, Terminated Non-PEO NEO Non-PEO NEO [Member] Cal Am California American Water Company [Member] California American Water Company Senior note - fixed rate Senior Notes [Member] Entity Address, Address Line One Entity Address, Address Line One Right-of-use asset obtained in exchange for operating lease liability Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Gain from termination of derivative instruments Gain (Loss) From Termination Of Derivative Instruments Gain (Loss) From Termination Of Derivative Instruments Provision for income taxes Provision for (benefit from) income taxes Income Tax Expense (Benefit) Unbilled revenues Business Combination, Recognized Asset Acquired, Unbilled Revenues Business Combination, Recognized Asset Acquired, Unbilled Revenues Wastewater Services Wastewater Services [Member] Wastewater Services [Member] Regulatory and other long-term assets: Regulated Entity, Other Assets, Noncurrent [Abstract] Award Timing Method Award Timing Method [Text Block] Net increase (decrease) in cash, cash equivalents and restricted funds Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Forecast Forecast [Member] Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Daily production, number of gallons related to desalinated water Public Utility, Daily Production, Number of Gallons Related to Desalinated Water Public Utility, Daily Production, Number of Gallons Related to Desalinated Water Liabilities assumed Business Combination and Asset Acquisition, Liabilities Business Combination and Asset Acquisition, Liabilities Amortization of actuarial loss Defined Benefit Plan, Amortization of Gain (Loss) Significant Accounting Policies Accounting Standards Update and Change in Accounting Principle [Text Block] AOCI Attributable to Parent, Net of Tax [Roll Forward] AOCI Attributable to Parent, Net of Tax [Roll Forward] Net income attributable to common shareholders Net income attributable to common shareholders Net income Net income attributable to common shareholders Net Income (Loss) Attributable to Parent Long-term Debt, Type Long-Term Debt, Type [Axis] Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Balance Sheet Location Location, Statement of Financial Position, Balance [Axis] General rate case authorizations, revenue, partial settlement, increase (decrease) amount Public Utilities, General Rate Case Authorizations, Revenue, Partial Settlement, Increase (Decrease) Amount Public Utilities, General Rate Case Authorizations, Revenue, Partial Settlement, Increase (Decrease) Amount Statement [Table] Statement [Table] Treasury Lock Agreements Treasury Lock [Member] Authorized return on equity, percentage Public Utilities, Approved Return on Equity, Percentage Restatement Determination Date: Restatement Determination Date [Axis] Payments, year three Lessee, Operating and Financing Lease, Liability, Payments, Due Year Three Lessee, Operating and Financing Lease, Liability, Payments, Due Year Three Schedule of Accumulated Other Comprehensive Loss Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Liabilities assumed: Business Combination, Recognized Liability Assumed, Liability [Abstract] Litigation settlement, proposed maximum pre-tax amount Litigation Settlement, Amount Awarded to Other Party Operating revenues Operating revenues Operating revenues Regulated and Unregulated Operating Revenue Cash and Cash Equivalents Cash and Cash Equivalents [Axis] Loss contingency, probable loss, net of tax Loss Contingency Accrual, Net of Tax Loss Contingency Accrual, Net of Tax Share-based awards Share-Based Payment Arrangement [Member] Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Numerator: Net Income (Loss) Available to Common Stockholders, Diluted [Abstract]