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Subsequent Event Subsequent Event [Member] Document Fiscal Year Focus Document Fiscal Year Focus Weighted average interest rates Debt, Weighted Average Interest Rate Adjustment to Compensation, Amount Adjustment to Compensation Amount Financial Instrument Financial Instrument [Axis] 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 Customer Customer [Axis] Segment Reporting [Abstract] Segment Reporting [Abstract] Various Debt Maturing in 2027 Through 2058 Various Debt Maturing in 2027 Through 2058 [Member] Various Debt Maturing in 2027 Through 2058 Common stock ($0.01 par value; 500,000,000 shares authorized; 204,242,057 and 200,605,170 shares issued, respectively) Common Stock, Value, Issued Future minimum sublease rentals, year one Lessee, Operating Lease, Liability, to be Paid, Year One Authorized rate base amount Public Utilities, Authorized Rate Base, Amount Public Utilities, Authorized Rate Base, Amount Public Utilities, General Disclosures Public Utilities, General Disclosures [Line Items] Outstanding debt Commercial Paper and Line of Credit Facility, Outstanding Commercial Paper and Line of Credit Facility, Outstanding 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 Pension and Other Postretirement Benefits Retirement Benefits [Text Block] Loss contingency, probable loss Loss Contingency Accrual Missouri MISSOURI Leases Lessee, Finance Leases [Text Block] Restatement Determination Date Restatement Determination Date 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 Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Derivative Instrument Derivative Instrument [Axis] Regulatory liabilities Regulatory Liability, Noncurrent Uncertain tax liabilities Unrecognized Tax Benefits, Period Increase (Decrease) Amendment Flag Amendment Flag Current liabilities: Liabilities, Current [Abstract] Provision for losses on accounts receivable Amounts charged to expense Accounts Receivable, Credit Loss Expense (Reversal) Line of credit facility, accordion feature, increase limit Line of Credit Facility, Accordion Feature, Increase Limit Line of Credit Facility, Accordion Feature, Increase Limit Other revenues not from contracts with customers Revenue Not from Contract with Customer, Other Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Disposal Group Classification Disposal Group Classification [Axis] Public Utility, Authorization, Effective Date, Year 2028 Public Utility, Authorization, Effective Date, Year 2028 [Member] Public Utility, Authorization, Effective Date, Year 2028 Debt securities, available-for-sale, accumulated gross unrealized loss Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax Property, plant and equipment, net Business Combination, Recognized Asset Acquired, Property, Plant, and Equipment Monterey Monterey [Member] Monterey Other Utilities Operating Expense (Credit), Other Utilities Operating Expense (Credit), Other Commercial Commercial [Member] Commercial [Member] Cal Am California American Water Company [Member] California American Water Company Leases [Abstract] Leases [Abstract] Other comprehensive income (loss), net of tax: Other Comprehensive Income (Loss), Net of Tax [Abstract] Number of dismissed claims Loss Contingency, Claims Dismissed, Number Number of denied regulatory application Litigation Settlement, Amount Awarded from Other Party, Benefit To Customer, Regulatory Approval, Number Of Denied Applications Litigation Settlement, Amount Awarded from Other Party, Benefit To Customer, Regulatory Approval, Number Of Denied Applications Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Schedule of Cash and Cash Equivalents Schedule of Cash and Cash Equivalents [Table Text Block] Entity Address, State or Province Entity Address, State or Province Kentucky KENTUCKY PEO Total Compensation Amount PEO Total Compensation Amount Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Cash paid for capital expenditures Segment Reporting, Long-Lived Asset, Expenditure for Addition Basic (in shares) Weighted-average common shares outstanding - basic (in shares) Weighted Average Number of Shares Outstanding, Basic Contract asset, current Contract with Customer, Asset, after Allowance for Credit Loss, Current Retirement Benefits [Abstract] Retirement Benefits [Abstract] Availability on Revolving Credit Facility Commercial Paper and Line of Credit Facility, Remaining Borrowing Capacity Commercial Paper and Line of Credit Facility, Remaining Borrowing Capacity Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Total capitalization Capitalization, Long-Term Debt and Equity Regulatory assets Regulatory Asset, Noncurrent Number of reportable segments Number of Reportable Segments Total current liabilities Liabilities, Current Future minimum sublease rentals, year four Lessee, Operating Lease, Liability, to be Paid, Year Four Number of agreements, valid Loss Contingency, Number of Agreements, Valid Loss Contingency, Number of Agreements, Valid Maryland MARYLAND Short-term Debt, Type Short-Term Debt, Type [Domain] Entity Address, City or Town Entity Address, City or Town Transfers to operating revenues Contract with Customer, Liability, Revenue Recognized, Including Additions, Net Contract with Customer, Liability, Revenue Recognized, Including Additions, Net Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Unbilled revenues Business Combination, Recognized Asset Acquired, Unbilled Revenues Business Combination, Recognized Asset Acquired, Unbilled Revenues Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Number of customers in service Business Combination, Number of Customers In Service Business Combination, Number of Customers In Service Senior Note 4.625% Due 2029 Senior Note 4.625% Due 2029 [Member] Senior Note 4.625% Due 2029 Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Net income attributable to common shareholders, basic Net Income (Loss) Available to Common Stockholders, Basic 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 Pension contributions Increase (Decrease) in Obligation, Pension Benefits Public Utility, Authorization, Effective Date, March 1, 2026 Public Utility, Authorization, Effective Date, March 1, 2026 [Member] Public Utility, Authorization, Effective Date, March 1, 2026 Level 2 Fair Value, Inputs, Level 2 [Member] Other (expense) income: Nonoperating Income (Expense) [Abstract] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] WVPSC Public Service Commission of West Virginia [Member] Public Service Commission of West Virginia Letters of credit, maximum borrowing capacity Total availability Line of Credit Facility, Maximum Borrowing Capacity Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Subsequent Event Type Subsequent Event Type [Axis] Preferred stock with mandatory redemption requirements, fair value Mandatorily Redeemable Preferred Stock, Fair Value Disclosure Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] New Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Other current liabilities Business Combination, Recognized Liability Assumed, Other Liability, Current New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Capital expenditures acquired on account but unpaid as of the end of period Capital Expenditures Incurred but Not yet Paid Private activity bonds and government funded debt Private Activity Bonds And Government Funded Debt [Member] Private activity bonds and government funded debt. Schedule of Summarized Segment Information Segment Reporting [Table Text Block] Unrealized gain (loss) on cash flow hedges, tax Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax Regulatory and other long-term liabilities: Liabilities, Other than Long-Term Debt, Noncurrent [Abstract] Net other comprehensive income (loss) Net other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Settlements of long-term debt Settlements Of Long Term Debt Settlements Of Long Term Debt Long-term debt, carrying amount Long-Term Debt Forward Sale Agreements Forward Sale Agreements [Member] Forward Sale Agreements Allowance for funds used during construction Public Utilities, Allowance for Funds Used During Construction Public Utilities, Allowance for Funds Used During Construction Loss contingency, estimated reasonably possible loss, amount Loss Contingency, Estimated Reasonably Possible Loss, Amount Loss Contingency, Estimated Reasonably Possible Loss, Amount Non-cash investing and financing activity Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Document Period End Date Document Period End Date Changes in assets and liabilities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] Unrealized gain (loss) on available-for-sale fixed-income securities, tax OCI, Debt Securities, Available-for-Sale, Gain (Loss), before Adjustment, Tax Net cash used in investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Debt instrument, face amount Debt Instrument, Face Amount Future minimum sublease rentals, year two Lessee, Operating Lease, Liability, to be Paid, Year Two Shareholders' Equity Equity [Text Block] Basic earnings per share: Earnings Per Share, Basic [Abstract] Security Exchange Name Security Exchange Name Number of focused general investigations Number of Focused General Investigations Number of Focused General Investigations Debt instrument, term Debt Instrument, Term Treasury stock, at cost (5,137,493 and 5,428,008 shares, respectively) Treasury Stock, Common, Value Regulatory Matters Regulatory Matters [Text Block] Regulatory Matters Regulated Businesses Regulated Business [Member] Regulated business. 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Adjustment, Net Transition Attributable to Parent [Member] General rate case authorizations, revenue, partial settlement, amount Public Utilities, General Rate Case Authorizations, Revenue, Partial Settlement, Amount Public Utilities, General Rate Case Authorizations, Revenue, Partial Settlement, Amount Diluted earnings per share: Earnings Per Share, Diluted [Abstract] Credit Facility Credit Facility [Domain] Compensation Amount Outstanding Recovery Compensation Amount Individual: Individual [Axis] Diluted (in shares) Weighted-average common shares outstanding - diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Dividends cash paid per common share (in dollars per share) Common Stock, Dividends, Per Share, Cash Paid Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Entity Emerging Growth Company Entity Emerging Growth Company Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] Preferred stock with mandatory redemption requirements, carrying amount Preferred Stocks With Mandatory Redemption Requirements Carrying Amount Preferred Stocks With Mandatory Redemption Requirements Carrying Amount Mountaineer Gas Company Mountaineer Gas Company [Member] Mountaineer Gas Company Net identifiable assets acquired Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less) Disposal Group Name Disposal Group Name [Domain] 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 Underlying Security Market Price Change Underlying Security Market Price Change, Percent Deferred income taxes and amortization of investment tax credits Deferred Income Taxes and Tax Credits Property, plant and equipment, net Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, 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Tax Rate Reconciliation, Percent Common equity, percentage Public Utilities, Common Equity Ratio Percentage Public Utilities, Common Equity Ratio Percentage Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Water supply projected area Area of Real Estate Property Contract assets: Change in Contract with Customer, Asset [Abstract] All Executive Categories All Executive Categories [Member] Regulated Operations [Abstract] Regulated Operations [Abstract] Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Long-term debt, fair value Long-Term Debt, Fair Value Schedule of Components of Net Periodic Benefit Costs Schedule of Net Benefit Costs [Table Text Block] Advances and contributions in aid of construction, refunds Repayments of Construction Loans Payable Antidilutive Securities [Axis] Antidilutive Securities [Axis] Scenario [Domain] Scenario [Domain] Number 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of Equity Award Amounts Reported in Summary Compensation Table [Member] Unbilled revenues Unbilled Receivables, Current Disposal Group, Including Discontinued Operations [Line Items] Disposal Group, Including Discontinued Operations [Line Items] Common equity, adjustment, percentage Public Utilities, Adjustment, Common Equity Ratio Percentage Public Utilities, Adjustment, Common Equity Ratio Percentage Loss contingency, possible loss Loss Contingency, Estimate of Possible Loss Business Combination [Line Items] Business Combination [Line Items] Net periodic benefit cost (credit) Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Acquisition financed by treasury stock Noncash or Part Noncash Acquisition, Treasury Stock Reissued, Value Noncash or Part Noncash Acquisition, Treasury Stock Reissued, Value Proceeds from the issuance of common stock Net proceeds Proceeds from Issuance of Common Stock 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 Common stock, shares authorized (in shares) Common Stock, Shares Authorized Antidilutive Security, Excluded EPS Calculation [Table] Antidilutive Security, Excluded EPS Calculation [Table] Accounts receivable, net of allowance for uncollectible accounts Business Combination, Recognized Asset Acquired, Receivable, Current Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Issuance of shares (in shares) Sale of Stock, Number of Shares Issued in Transaction Exercise Price Award Exercise Price Segment Reporting [Line Items] Segment Reporting [Line Items] Operating and Maintenance Agreement Operating and Maintenance Agreement [Member] Operating and Maintenance Agreement [Member] Approved cost estimates Public Utility, Approved Cost Estimates Public Utility, Approved Cost Estimates Proceeds from sales and maturities of available-for-sale fixed-income securities Proceeds from Sale and Maturity of Debt Securities, Available-for-Sale Document Quarterly Report Document Quarterly Report Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Segments Segments [Domain] Total availability Commercial Paper Maximum Borrowing Capacity Commercial Paper Maximum Borrowing Capacity Property, Plant and Equipment Property, Plant, and Equipment [Policy Text Block] Scenario [Axis] Scenario [Axis] Repayments of long-term debt Repayments of Long-Term 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Liabilities Business Combination, Recognized Liability Assumed, Regulatory Liabilities Adoption Date Trading Arrangement Adoption Date Consideration Disposal Group, Including Discontinued Operation, Consideration Contract liabilities: Contract with Customer, Liability [Abstract] Interest rate Debt Instrument, Interest Rate, Stated Percentage Total common shareholders' equity Beginning balance Ending balance Equity, Attributable to Parent Authorization, Effective Date Public Utility, Authorization, Effective Date [Axis] Public Utility, Authorization, Effective Date Total other (expense) income Nonoperating Income (Expense) Disposal Group, Disposed of by Sale Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] Real Estate Real Estate [Domain] Accrued taxes Increase (Decrease) in Accrued Taxes Payable Aggregate costs Public Utilities, Aggregate Costs Public Utilities, Aggregate Costs 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 Investment tax credit Investment Tax Credit Schedule of Annualized Incremental Revenues Schedule of Annualized Incremental Revenues [Table Text Block] Schedule of Annualized Incremental Revenues ASSETS Assets: Assets [Abstract] Regulatory Agency Regulatory Agency [Axis] Year 2027 Public Utility Authorization Effective Date January 1, 2027 [Member] Public Utility Authorization Effective Date January 1, 2027 Title Trading Arrangement, Individual Title Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Number of shares issued in business combination (in shares) Business Combination, Consideration Transferred, Equity Interest, Share Issued, Number of Shares Debt securities, available-for-sale, amortized cost Debt Securities, Available-for-Sale, Amortized Cost Remaining availability Commercial Paper Remaining Borrowing Capacity Remaining borrowing capacity of commercial paper (current borrowing capacity less the amount of borrowings outstanding). 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Accrued pension expense Liability, Defined Benefit Pension Plan, Noncurrent Name Forgone Recovery, Individual Name Liabilities assumed Business Combination and Asset Acquisition, Liabilities Business Combination and Asset Acquisition, Liabilities Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Non-equity, percentage Public Utilities, Non-Equity Ratio Percentage Public Utilities, Non-Equity Ratio Percentage Senior Note 3.000% Due 2026 Senior Note 3.000% Due 2026 [Member] Senior Note 3.000% Due 2026 Statement [Line Items] Statement [Line Items] Total assets Total assets Assets Schedule of Defined Benefit Plans Disclosures [Table] Defined Benefit Plan [Table] Entity Entity [Domain] Exchangeable Senior Note 3.625% Due 2026 Exchangeable Senior Note 3.625% Due 2026 [Member] Exchangeable Senior Note 3.625% Due 2026 Defined benefit pension plan actuarial loss, net of tax of $0 for the three and nine months ended September 30, 2026 and 2025 Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax Exchangeable Debt Convertible Debt [Member] New Accounting Pronouncements and Changes in Accounting Principles [Abstract] Accounting Standards Update and Change in Accounting Principle [Abstract] Amortization of prior service credit Defined Benefit 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 September 30, 2026 and 2025, and $0 and $(1) for the nine months ended September 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) Total liabilities assumed Business Combination, Recognized Liability Assumed, Liability Other comprehensive (loss) income before reclassifications OCI, before Reclassifications, Net of Tax, Attributable to Parent Increase on interest on unrecognized tax benefits Unrecognized Tax Benefits, Increase (Decrease) In Interest Unrecognized Tax Benefits, Increase (Decrease) In Interest PEO PEO [Member] Cash and Cash Equivalents Cash and Cash Equivalents [Domain] Escrow funds transferred Litigation Settlement, Amount Awarded From Other Party, Escrow, Transfers Litigation Settlement, Amount Awarded From Other Party, Escrow, Transfers 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 Fixed Income Securities [Member] Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Goodwill related to acquisition Goodwill, Acquired During Period Secured seller promissory note from the sale of the Homeowner Services Group Financing Receivable, after Allowance for Credit Loss, Noncurrent Accounts payable Business Combination, Recognized Liability Assumed, Accounts Payable, Current Cost cap for proposed facilities, final Loss Contingency, Cost Cap For Proposed Facilities Loss Contingency, Cost Cap For Proposed Facilities 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] 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] Number of acquisitions Number of Assets Acquired from Business Combination and Asset Acquisition Number of Assets Acquired from Business Combination and Asset Acquisition 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] Entity Current Reporting Status Entity Current Reporting Status Net cash provided by financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Number of customers in service Business Combination and Asset Acquisition, Number of Customers In Service Business Combination and Asset Acquisition, Number of Customers In Service Total Shareholder Return Amount Total Shareholder Return Amount Updated cost estimate, pending approval Public Utility, Pending Cost Estimates Public Utility, Pending Cost Estimates 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 Other Corporate And Reconciling Items [Member] Corporate And Reconciling Items U.S. Government U.S. Government [Member] U.S. Government [Member] Operation and maintenance 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] Total availability Commercial Paper and Line of Credit Facility, Maximum Borrowing Capacity Commercial Paper and Line of Credit Facility, Maximum Borrowing Capacity Amounts written off Accounts Receivable, Allowance for Credit Loss, Writeoff Total identifiable assets Business Combination, Recognized Asset Acquired, Asset Investment tax credit, period Investment Tax Credit, Period Investment Tax Credit, Period General rate case authorizations, revenue, revised requested rate increase, amount Public Utilities, General Rate Case Authorizations, Revenue, Revised Requested Rate Increase (Decrease), Amount Public Utilities, General Rate Case Authorizations, Revenue, Revised Requested Rate Increase (Decrease), Amount Revenues from Contracts with Customers Revenue from Contract with Customer, Excluding Assessed Tax Aggregate purchase price Business Combination and Asset Acquisition, Consideration Transferred Business Combination and Asset Acquisition, Consideration Transferred Remaining availability Line of Credit Facility, Remaining Borrowing Capacity Interest cost Defined Benefit Plan, Interest Cost Miscellaneous utility charges Miscellaneous Utility Charge [Member] Miscellaneous Utility Charge [Member] Financial Instruments Financial Instruments [Domain] Number of applications pending Litigation Settlement, Amount Awarded from Other Party, Benefit To Customer, Regulatory Approval, Number Of Pending Litigation Settlement, Amount Awarded from Other Party, Benefit To Customer, Regulatory Approval, Number Of Pending Deposits Deposit Assets, Fair Value Disclosure Deposit Assets, Fair Value Disclosure Mark-to-market derivative asset Derivative Asset Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Public utilities, authorized rate base not included in general rate case order, amount Public Utilities, Authorized Rate Base Not Included In General Rate Case Order, Amount Public Utilities, Authorized Rate Base Not Included In General Rate Case Order, Amount Underlying Securities Award Underlying Securities Amount Approved recovery amount Public Utility, Approved Recovery Amount Public Utility, Approved Recovery 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] Alternative revenue programs Alternative Revenue Programs Alternative Revenue Programs Number of employees Business Combination and Asset Acquisition, Number of Employees Business Combination and Asset Acquisition, Number of Employees Exchangeable Notes Exchangeable Notes [Member] Exchangeable Notes Public Utility, Authorization, Effective Date, Year 2027 Public Utility, Authorization, Effective Date, Year 2027 [Member] Public Utility, Authorization, Effective Date, Year 2027 Operating lease, weighted-average discount rate Operating Lease, Weighted Average Discount Rate, Percent Cost cap for extraction wells Loss Contingency, Cost Cap For Proposed Facilities, Increase Loss Contingency, Cost Cap For Proposed Facilities, Increase Segment Reporting [Table] Segment Reporting [Table] Expected contributions, remainder of fiscal year Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year 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 Derivative, number of instruments held Derivative, Number of Instruments Held Stockholders Equity [Table] Stockholders Equity [Table] Stockholders Equity 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 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 Potential condemnation, asset value Potential Condemnation, Asset Value Potential Condemnation, Asset Value CASH FLOWS FROM OPERATING ACTIVITIES Cash Provided by (Used in) Operating Activity, Continuing Operation [Abstract] Approved debt component (as a percent) Public Utilities, Approved Debt Capital Structure, Percentage 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 Senior Note 5.550% Due 2033 Senior Note 5.550% Due 2033 [Member] Senior Note 5.550% Due 2033 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 Real Property Land, Buildings and Improvements [Member] Senior Note 5.200% Due 2036 Senior Note 5.200% Due 2036 [Member] Senior Note 5.200% Due 2036 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] 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 Number of business combination and asset acquisition acquired Number Of Acquisitions Accounted For As Business Combination Number Of Business Combination and Asset Acquisition Acquired Gordon's Corner Water Company Gordon's Corner Water Company [Member] Gordons Corner Water Company Treasury stock, shares (in shares) Beginning balance (in shares) Ending balance (in shares) Treasury Stock, Common, Shares Loss contingency, probable loss, net of tax Loss Contingency Accrual, Net of Tax Loss Contingency Accrual, Net of Tax Removal costs from property, plant and equipment retirements, net Payments for (Proceeds from) Removal Costs Equity Components Equity Components [Axis] 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] Capitalization: Capitalization, Long-Term Debt and Equity [Abstract] Entity Interactive Data Current Entity Interactive Data Current 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 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] Assets acquired Business Combination and Asset Acquisition, Assets Business Combination and Asset Acquisition, Assets Number of agreements Loss Contingency, Number of Agreements Loss Contingency, Number of Agreements 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 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] Proceeds from long-term debt, net of discount Proceeds from Issuance of Long-Term Debt 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 Approved equity component (as a percent) Public Utilities, Approved Equity Capital Structure, Percentage 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] 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 Executive Category: Executive Category [Axis] Public Utility, Authorization, Effective Date, Year 2029 Public Utility, Authorization, Effective Date, Year 2029 [Member] Public Utility, Authorization, Effective Date, Year 2029 CAPITALIZATION AND LIABILITIES Liabilities and Equity [Abstract] Thereafter Lessee, Operating and Financing Lease, Liability, Payments, Due after Year Four Lessee, Operating and Financing Lease, Liability, Payments, Due after Year Four Other investments Other Investments, Fair Value Disclosure Other Investments, Fair Value Disclosure 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] 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 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 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] Schedule of Generate Rate Cases and Infrastructure Surcharges Schedule of Generate Rate Cases and Infrastructure Surcharges [Table Text Block] Schedule of Generate Rate Cases and Infrastructure Surcharges Unrealized gain (loss) on cash flow hedges, net of tax of $1 and $0 for the three months ended September 30, 2026 and 2025, respectively, and $1 and $(2) for the nine months ended September 30, 2026 and 2025, respectively Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax Number of customers serving Number of Customer Serving Number of Customer Serving Year 2026 Public Utility Authorization Effective Date February 26, 2026 [Member] Public Utility Authorization Effective Date February 26, 2026 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 Year 2025 Public Utility, Authorization, Effective Date, Year 2025 [Member] Public Utility, Authorization, Effective Date, Year 2025 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] 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] Wastewater Services Wastewater Services [Member] Wastewater Services [Member] General taxes Utilities Operating Expense, Taxes Dividends (declared per common share) Dividends, Cash Potential condemnation, number of statutory standards incorrectly applied by agency Potential Condemnation, Number of Statutory Standards Incorrectly Applied By Agency Potential Condemnation, Number of Statutory Standards Incorrectly Applied By Agency Allowance for Uncollectible Accounts Credit Loss, Financial Instrument [Policy Text Block] Number of new subsurface slant wells Number Of Subsurface Slant Wells Number Of Subsurface Slant Wells 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] Net income attributable to common shareholders (in dollars per share) Earnings Per Share, Basic Imputed interest Lessee, Operating and Financing Lease, Liability, Undiscounted Excess Amount Lessee, Operating and Financing Lease, Liability, Undiscounted Excess Amount Contract liability, current Contract with Customer, Liability, Current Total current assets Assets, Current Range Statistical Measurement [Axis] Insider Trading Arrangements [Line Items] Award Type Award Type [Axis] Number of utility subsidiaries Litigation Settlement, Amount Awarded from Other Party, Benefit To Customer, Regulatory Approval, Number Of Utility Subsidiaries Litigation Settlement, Amount Awarded from Other Party, Benefit To Customer, Regulatory Approval, Number Of Utility Subsidiaries Debt issuance costs Payments of Financing Costs Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Accounts receivable, net of allowance for uncollectible accounts of $68 and $58, respectively Accounts Receivable, after Allowance for Credit Loss, Current Retained earnings Retained Earnings (Accumulated Deficit) Total Available Liquidity Cash, Cash Equivalents, and Short-Term Debt Liquidity Cash, Cash Equivalents, and Short-Term Debt Liquidity Products and Services Product and Service [Axis] Long-term restricted funds Restricted Cash, Noncurrent Commitments And Contingencies [Table] Commitments And Contingencies [Table] Commitments and contingencies. General rate case authorizations, annualized incremental revenues, estimated and not approved amount Public Utilities, General Rate Case Authorizations, Annualized Incremental Revenues, Estimated and Not Approved Amount Public Utilities, General Rate Case Authorizations, Annualized Incremental Revenues, Estimated and Not Approved Amount 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] Payments, remainder of fiscal year Lessee, Operating and Financing Lease, Liability, Payments, Remainder Of Fiscal Year Lessee, Operating and Financing Lease, Liability, Payments, Remainder Of Fiscal Year Deferred compensation obligations Obligations, Fair Value Disclosure Pension Benefits Pension Plan [Member] Short-term Debt [Line Items] Short-Term Debt [Line Items] Investment tax credit, sold to external parties Investment Tax Credit, Sold To External Parties Investment Tax Credit, Sold To External Parties Common Stock Common Stock [Member] Debt securities, available-for-sale fair value Debt Securities, Available-for-Sale Portion at Fair Value Measurement Fair Value Measurement [Domain] Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Cover [Abstract] Cover [Abstract] Non-operating benefit costs, net Benefit Costs, Non-Operating, Net Benefit Costs, Non-Operating, Net Treasury lock agreements, Designated as Hedging Instrument, Terminated, Transaction 2 Treasury lock agreements, Designated as Hedging Instrument, Terminated, Transaction 2 [Member] Treasury lock agreements, Designated as Hedging Instrument, Terminated, Transaction 2 General rate case authorizations, annualized incremental revenues, projected infrastructure filings amount Public Utilities, General Rate Case Authorizations, Annualized Incremental Revenues, Projected Infrastructure Filings Amount Public Utilities, General Rate Case Authorizations, Annualized Incremental Revenues, Projected Infrastructure Filings Amount Derivative Contract Derivative Contract [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 Public Utilities General Disclosures Public Utilities General Disclosures [Table] Merger transaction, share exchange ratio Merger Transaction, Share Exchange Ratio Merger Transaction, Share Exchange Ratio Equity Awards Adjustments Equity Awards Adjustments [Member] Number of customers who completed claim process Number of Customers Who Completed Claim Process Number of Customers Who Completed Claim Process Total capitalization and liabilities Liabilities and Equity Employee Stock Option Share-Based Payment Arrangement, Option [Member] Segments Segments [Axis] Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Tabular List, Table Tabular List [Table Text Block] Restricted funds included in other long-term assets Restricted Cash and Cash Equivalent, Noncurrent Number of customers affected by loss of natural gas service Number of Customer Affected By Loss of Natural Gas Service Number of Customer Affected By Loss of Natural Gas Service 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, net Other Nonoperating Income (Expense) Homeowner Services Group Homeowner Services Group [Member] Homeowner Services Group Long-Term Debt Long-Term Debt [Text Block] Year 2026 Public Utility, Authorization, Effective Date, Year 2026 [Member] Public Utility, Authorization, Effective Date, Year 2026 Income tax receivable Income Taxes Receivable, Current Name Awards Close in Time to MNPI Disclosures, Individual Name 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] Mountaineer Gas Company and WVAWC Mountaineer Gas Company and West Virginia American Water Company [Member] Mountaineer Gas Company and West Virginia American Water Company Authorization, Effective Date Public Utility, Authorization, Effective Date [Domain] Public Utility, Authorization, Effective Date [Domain] 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 Utility Plant Utility Plant [Member] Utility plant. Materials and supplies Inventory, Raw Materials and Supplies, Gross Total regulatory and other long-term liabilities Regulatory and Other Long-term Liabilities Regulatory and Other Long-term Liabilities Advances for construction Advances for Construction Advances for Construction Adjustment to Compensation: Adjustment to Compensation [Axis] 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 American Water Capital Corp. American Water Capital Corp A W C C [Member] American Water Capital Corp AWCC. 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) Initial daily production, number of gallons related to desalinated water Public Utility, Initial Daily Production, Number of Gallons Related to Desalinated Water Public Utility, Initial Daily Production, Number of Gallons Related to Desalinated Water Debt Instrument [Line Items] Debt Instrument [Line Items] Rabbi trust investments Rabbi Trust Investments Rabbi trust investments. Dunbar Dunbar [Member] Dunbar. Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Potential condemnation, parcels of land Potential Condemnation, Parcels of Land Potential Condemnation, Parcels of Land Total consideration for business combination Business Combination, Consideration Transferred Retirement Plan Type Retirement Plan Type [Domain] Year 2024 Public Utility, Authorization, Effective Date, Year 2024 [Member] Public Utility, Authorization, Effective Date, Year 2024 Paid-in-Capital Additional Paid-in Capital [Member] Entity Filer Category Entity Filer Category Potential condemnation, offer rejection amount Potential Condemnation, Offer Rejection Amount Potential Condemnation, Offer Rejection Amount Equipment Equipment [Member] Fire service Fire Service [Member] Fire Service [Member] Nexus Water Group Inc. Nexus Water Group Inc. [Member] Nexus Water Group Inc. Total escrow account funds held in law firm Litigation Settlement, Amount Awarded From Other Party, Escrow Litigation Settlement, Amount Awarded From Other Party, Escrow Essential Utilities, Inc. Essential Utilities, Inc. [Member] Essential Utilities, Inc. Name Trading Arrangement, Individual Name Cash and cash equivalents Cash and Cash Equivalents Cash and Cash Equivalent Debt instrument, amortization period Debt Instrument, Amortization Period Debt Instrument, Amortization Period 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 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 Non-PEO NEO Non-PEO NEO [Member] 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 Provision for income taxes Provision for (benefit from) income taxes Income Tax Expense (Benefit) 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 Stockholders Equity [Line items] Stockholders Equity [Line Items] Stockholders Equity Interest income Interest income Interest income Interest Income, Nonoperating Interest Income, Nonoperating Regulatory and other long-term assets: Regulated Entity, Other Assets, Noncurrent [Abstract] Award Timing Method Award Timing Method [Text Block] Net increase 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] General rate case authorizations, annualized incremental revenues, requested rate, increase in capital investments Public Utilities, General Rate Case Authorizations, Annualized Incremental Revenues, Requested Rate, Increase (Decrease) In Capital Investments Public Utilities, General Rate Case Authorizations, Annualized Incremental Revenues, Requested Rate, Increase (Decrease) In Capital Investments Total infrastructure surcharge authorizations Public Utilities, Infrastructure Surcharge Authorizations Public Utilities, Infrastructure Surcharge Authorizations 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 (loss) 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] Statement [Table] Statement [Table] Treasury Lock Agreements Treasury Lock [Member] Regulatory assets Business Combination, Recognized Asset Acquired, Regulatory Assets Business Combination, Recognized Asset Acquired, Regulatory Assets Authorized return on equity, percentage Public Utilities, Approved Return on Equity, Percentage Restatement Determination Date: Restatement Determination Date [Axis] Schedule of Accumulated Other Comprehensive Loss Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] 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 Residential Residential [Member] Residential [Member] Total long-term debt Long Term Debt Includes Redeemable Preferred Stock At Redemption Value Long-term debt includes redeemable preferred stock at redemption value. Liabilities assumed: Business Combination, Recognized Liability Assumed, Liability [Abstract] Litigation settlement, proposed maximum pre-tax amount Litigation Settlement, Amount Awarded to Other Party Debt ratio, percentage Public Utilities, Debt Ratio Percentage Public Utilities, Debt Ratio Percentage Operating revenues Operating revenues Operating revenues Regulated and Unregulated Operating Revenue Cash and Cash Equivalents Cash and Cash Equivalents [Axis] Share-based awards Share-Based Payment Arrangement [Member] Payments, year four Lessee, Operating and Financing Lease, Liability, Payments, Due Year Four Lessee, Operating and Financing Lease, Liability, Payments, Due Year Four Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Numerator: Net Income (Loss) Available to Common Stockholders, Diluted [Abstract]