CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - OPCo - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
Adjustments to Reconcile Net Income to Net Cash Flows from Operating Activities:
Depreciation and Amortization	$ 2,566.1	$ 2,461.7
Deferred Income Taxes	123.6	89.5
Asset Impairments and Other Related Charges	0.0	142.5
Allowance for Equity Funds Used During Construction	(172.9)	(153.0)
Mark-to-Market of Risk Management Contracts	(192.6)	(97.6)
Property Taxes	541.3	508.3
Change in Other Noncurrent Assets	(719.7)	(244.0)
Change in Other Noncurrent Liabilities	133.8	193.8
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	(212.4)	(131.8)
Materials and Supplies	150.7	188.5
Accounts Payable	327.3	14.2
Accrued Taxes, Net	(687.2)	(532.3)
Other Current Assets	37.7	(139.2)
Other Current Liabilities	74.3	161.8
Net Cash Flows from Operating Activities	5,130.8	5,076.9
INVESTING ACTIVITIES
Construction Expenditures	(6,001.2)	(5,168.6)
Other Investing Activities	43.5	73.0
Net Cash Flows Used for Investing Activities	(7,749.1)	(4,769.5)
FINANCING ACTIVITIES
Issuance of Long-term Debt	6,249.2	3,748.5
Principal Payments for Finance Lease Obligations	(37.9)	(51.2)
Dividends Paid on Common Stock	(1,497.9)	(1,402.7)
Other Financing Activities	2.8	(50.4)
Net Cash Flows from (Used for) Financing Activities	3,479.1	(387.2)
Net Increase in Cash and Cash Equivalents	860.8	(79.8)
Cash, Cash Equivalents and Restricted Cash at Beginning of Period	246.0	379.0
Cash, Cash Equivalents and Restricted Cash at End of Period	1,106.8	299.2
SUPPLEMENTARY INFORMATION
Cash Paid for Interest, Net of Capitalized Amounts	1,315.1	1,247.3
Net Cash Paid (Received) for Income Taxes	60.1	87.9
Noncash Acquisitions Under Finance Leases	30.0	24.5
Construction Expenditures Included in Current Liabilities as of September 30,	1,168.8	1,015.1
OPCo
OPERATING ACTIVITIES
Net Income	266.7	201.7
Adjustments to Reconcile Net Income to Net Cash Flows from Operating Activities:
Depreciation and Amortization	285.3	293.9
Deferred Income Taxes	33.9	0.2
Asset Impairments and Other Related Charges	0.0	52.9
Allowance for Equity Funds Used During Construction	(19.3)	(16.2)
Mark-to-Market of Risk Management Contracts	(3.2)	0.9
Property Taxes	306.4	286.6
Change in Other Noncurrent Assets	39.2	19.2
Change in Other Noncurrent Liabilities	(11.4)	47.2
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	48.4	(39.8)
Materials and Supplies	(10.2)	33.8
Accounts Payable	131.3	(43.4)
Customer Deposits	(7.7)	6.1
Accrued Taxes, Net	(416.0)	(322.3)
Other Current Assets	2.5	(11.9)
Other Current Liabilities	0.1	17.2
Net Cash Flows from Operating Activities	646.0	526.1
INVESTING ACTIVITIES
Construction Expenditures	(747.1)	(688.5)
Change in Advances to Affiliates, Net	114.9	(97.4)
Other Investing Activities	45.3	29.4
Net Cash Flows Used for Investing Activities	(586.9)	(756.5)
FINANCING ACTIVITIES
Capital Contribution from Parent	1.8	0.8
Issuance of Long-term Debt	0.0	346.3
Change in Advances from Affiliates, Net	13.0	(110.5)
Principal Payments for Finance Lease Obligations	(3.4)	(4.0)
Dividends Paid on Common Stock	(71.0)	0.0
Other Financing Activities	1.4	1.0
Net Cash Flows from (Used for) Financing Activities	(58.2)	233.6
Net Increase in Cash and Cash Equivalents	0.9	3.2
Cash, Cash Equivalents and Restricted Cash at Beginning of Period	4.5	6.4
Cash, Cash Equivalents and Restricted Cash at End of Period	5.4	9.6
SUPPLEMENTARY INFORMATION
Cash Paid for Interest, Net of Capitalized Amounts	90.6	82.8
Net Cash Paid (Received) for Income Taxes	53.1	(5.1)
Noncash Acquisitions Under Finance Leases	1.5	1.1
Construction Expenditures Included in Current Liabilities as of September 30,	$ 118.5	$ 126.8