| Current Federal Tax Expense (Benefit) | 151.00M | 2025-01-01 → 2025-12-31 |
| Current State and Local Tax Expense (Benefit) | 25.00M | 2025-01-01 → 2025-12-31 |
| Current Federal, State and Local, Tax Expense (Benefit) | 176.00M | 2025-01-01 → 2025-12-31 |
| Deferred Federal Income Tax Expense (Benefit) | 100.00M | 2025-01-01 → 2025-12-31 |
| Deferred State and Local Income Tax Expense (Benefit) | 36.00M | 2025-01-01 → 2025-12-31 |
| Deferred Federal, State and Local, Tax Expense (Benefit) | 135.00M | 2025-01-01 → 2025-12-31 |
| Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, before Accumulated Depreciation and Amortization | 37.95B | as of 2025-12-31 |
| Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, Accumulated Depreciation and Amortization | 7.38B | as of 2025-12-31 |
| Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization | 30.58B | as of 2025-12-31 |
| Share-based Payment Arrangement, Amount Capitalized | 0 | 2025-01-01 → 2025-12-31 |
| Share-based Payment Arrangement, Expense | 32.00M | 2025-01-01 → 2025-12-31 |
| Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount | 299.00M | 2025-01-01 → 2025-12-31 |
| Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount | 48.00M | 2025-01-01 → 2025-12-31 |
| Share-based Payment Arrangement, Expense, after Tax | 25.00M | 2025-01-01 → 2025-12-31 |
| Share-based Payment Arrangement, Expense, Tax Benefit | 7.00M | 2025-01-01 → 2025-12-31 |
| Contract with Customer, Asset, Reclassified to Receivable | 122.00M | 2025-01-01 → 2025-12-31 |
| Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount | 5.00M | 2025-01-01 → 2025-12-31 |
| Public Utilities, Property, Plant and Equipment, Construction Work in Progress | 1.55B | as of 2025-12-31 |
| SegmentExpenditureAdditionToLongLivedAssets | 3.13B | 2025-01-01 → 2025-12-31 |
| Effective Income Tax Rate Reconciliation, Tax Contingency, Amount | -8.00M | 2025-01-01 → 2025-12-31 |
| SegmentReportingOtherItemAmount | 280.00M | 2025-01-01 → 2025-12-31 |
| Public Utilities, Property, Plant and Equipment, Plant in Service | 37.85B | as of 2025-12-31 |
| Public Utilities, Property, Plant and Equipment, Net | 37.95B | as of 2025-12-31 |
| Effective Income Tax Rate Reconciliation, Other Adjustments, Amount | 6.00M | 2025-01-01 → 2025-12-31 |
| Litigation Settlement, Amount Awarded from Other Party | 159.00M | 2025-01-01 → 2025-12-31 |
| Loss Contingency Accrual | 8.00M | as of 2025-12-31 |
| Net Income (Loss) Available to Common Stockholders, Diluted | 1.11B | 2025-01-01 → 2025-12-31 |
| Regulatory Assets | 1.15B | as of 2025-12-31 |
| Regulatory Liabilities | 1.44B | as of 2025-12-31 |
| Deferred Tax Assets, Operating Loss Carryforwards | 215.00M | as of 2025-12-31 |
| Goodwill, Acquired During Period | 12.00M | 2025-01-01 → 2025-12-31 |
| Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax | 200.00M | as of 2025-12-31 |
| Unrecorded Unconditional Purchase Obligation, to be Paid, Year One | 83.00M | as of 2025-12-31 |
| Unrecorded Unconditional Purchase Obligation, to be Paid, Year Two | 77.00M | as of 2025-12-31 |
| Unrecorded Unconditional Purchase Obligation, to be Paid, Year Three | 78.00M | as of 2025-12-31 |
| Unrecorded Unconditional Purchase Obligation, to be Paid, Year Four | 79.00M | as of 2025-12-31 |
| Unrecorded Unconditional Purchase Obligation, to be Paid, Year Five | 55.00M | as of 2025-12-31 |
| Unrecorded Unconditional Purchase Obligation, to be Paid, after Year Five | 968.00M | as of 2025-12-31 |
| Goodwill, Gross | 3.60B | as of 2025-12-31 |
| Goodwill, Impaired, Accumulated Impairment Loss | 2.44B | as of 2025-12-31 |
| Right-of-Use Asset Obtained in Exchange for Operating Lease Liability | 8.00M | 2025-01-01 → 2025-12-31 |
| Contributions in Aid of Construction | 1.63B | as of 2025-12-31 |
| Accounts Receivable, Allowance for Credit Loss, Writeoff | 43.00M | 2025-01-01 → 2025-12-31 |
| Lessee, Operating Lease, Liability, to be Paid, Year One | 11.00M | as of 2025-12-31 |
| Lessee, Operating Lease, Liability, to be Paid, Year Two | 11.00M | as of 2025-12-31 |
| Lessee, Operating Lease, Liability, to be Paid, Year Three | 9.00M | as of 2025-12-31 |
| Deferred Tax Assets, Regulatory Assets and Liabilities | 161.00M | as of 2025-12-31 |
| Lessee, Operating Lease, Liability, to be Paid, Year Four | 8.00M | as of 2025-12-31 |
| Regulated and Unregulated Operating Revenue | 5.14B | 2025-01-01 → 2025-12-31 |
| Lessee, Operating Lease, Liability, to be Paid, Year Five | 6.00M | as of 2025-12-31 |
| Lessee, Operating Lease, Liability, to be Paid, after Year Five | 83.00M | as of 2025-12-31 |
| Deferred Tax Assets, Other | 166.00M | as of 2025-12-31 |
| Utilities Operating Expense, Maintenance and Operations | 2.02B | 2025-01-01 → 2025-12-31 |
| Utilities Operating Expense, Depreciation and Amortization | 894.00M | 2025-01-01 → 2025-12-31 |
| Deferred Tax Assets, Gross | 1.09B | as of 2025-12-31 |
| Utilities Operating Expense, Taxes | 348.00M | 2025-01-01 → 2025-12-31 |
| Deferred Tax Assets, Valuation Allowance | 9.00M | as of 2025-12-31 |
| Deferred Tax Assets, Net of Valuation Allowance | 1.08B | as of 2025-12-31 |
| Lessee, Operating Lease, Liability, Undiscounted Excess Amount | 46.00M | as of 2025-12-31 |
| Deferred Tax Liabilities, Gross | 4.25B | as of 2025-12-31 |
| Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount | 1.00M | 2025-01-01 → 2025-12-31 |
| Long-term Debt, Gross | 14.30B | as of 2025-12-31 |
| Deferred Tax Liabilities, Property, Plant and Equipment | 4.02B | as of 2025-12-31 |
| Assets, Fair Value Disclosure | 254.00M | as of 2025-12-31 |
| Obligations, Fair Value Disclosure | 38.00M | as of 2025-12-31 |
| Financial and Nonfinancial Liabilities, Fair Value Disclosure | 38.00M | as of 2025-12-31 |
| Fair Value, Net Asset (Liability) | 216.00M | as of 2025-12-31 |
| OCI, before Reclassifications, Net of Tax, Attributable to Parent | -3.00M | 2025-01-01 → 2025-12-31 |
| Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent | 3.00M | 2025-01-01 → 2025-12-31 |
| Deferred Tax Liabilities, Other | 157.00M | as of 2025-12-31 |
| Deferred Tax Liabilities, Net | 3.17B | as of 2025-12-31 |
| Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation | 849.00M | as of 2025-12-31 |
| Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Plan Assets | 743.00M | as of 2025-12-31 |
| Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation | 912.00M | as of 2025-12-31 |
| Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Plan Assets | 743.00M | as of 2025-12-31 |
| Unrecorded Unconditional Purchase Obligation, Purchases | 138.00M | 2025-01-01 → 2025-12-31 |
| Long-Term Debt, Maturity, Year One | 1.48B | as of 2025-12-31 |
| Defined Contribution Plan, Cost | 15.00M | 2025-01-01 → 2025-12-31 |
| Long-Term Debt, Maturity, Year Two | 646.00M | as of 2025-12-31 |
| Long-Term Debt, Maturity, Year Three | 869.00M | as of 2025-12-31 |
| Long-Term Debt, Maturity, Year Four | 938.00M | as of 2025-12-31 |
| Long-Term Debt, Maturity, Year Five | 517.00M | as of 2025-12-31 |
| Long-Term Debt, Maturity, after Year Five | 9.85B | as of 2025-12-31 |
| Capitalization, Long-term Debt and Equity | 23.62B | as of 2025-12-31 |
| Debt Instrument, Unamortized Discount (Premium), Net | 27.00M | as of 2025-12-31 |
| Debt Issuance Costs, Net | 17.00M | as of 2025-12-31 |
| Unrecognized Tax Benefits | 116.00M | as of 2025-12-31 |
| Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions | 31.00M | 2025-01-01 → 2025-12-31 |
| Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities | 118.00M | 2025-01-01 → 2025-12-31 |
| Income Taxes Receivable, Current | 9.00M | as of 2025-12-31 |
| Pension and Other Postretirement Benefits Cost (Reversal of Cost) | 1.00M | 2025-01-01 → 2025-12-31 |