CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - OPCo - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Adjustments to Reconcile Net Income to Net Cash Flows from Operating Activities:
Depreciation and Amortization	$ 833.4	$ 787.1
Deferred Income Taxes	165.2	(113.3)
Allowance for Equity Funds Used During Construction	(57.3)	(43.6)
Mark-to-Market of Risk Management Contracts	(14.8)	40.9
Property Taxes	(88.4)	(89.2)
Change in Other Noncurrent Assets	(130.9)	(74.5)
Change in Other Noncurrent Liabilities	141.5	61.8
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	(1.5)	34.9
Materials and Supplies	138.6	104.3
Accounts Payable	6.2	(99.5)
Accrued Taxes, Net	(153.4)	(57.7)
Other Current Assets	(23.6)	(91.3)
Other Current Liabilities	(92.7)	(66.8)
Net Cash Flows from Operating Activities	1,450.0	1,442.2
INVESTING ACTIVITIES
Construction Expenditures	(2,100.2)	(1,761.7)
Other Investing Activities	50.2	29.6
Net Cash Flows Used for Investing Activities	(2,102.0)	(1,669.3)
FINANCING ACTIVITIES
Principal Payments for Finance Lease Obligations	(12.5)	(17.0)
Dividends Paid on Common Stock	(501.0)	(466.9)
Other Financing Activities	(18.7)	(31.9)
Net Cash Flows from Financing Activities	698.0	129.9
Net Increase (Decrease) in Cash, Cash Equivalents and Restricted Cash	46.0	(97.2)
Cash, Cash Equivalents and Restricted Cash at Beginning of Period	246.0	379.0
Cash, Cash Equivalents and Restricted Cash at End of Period	292.0	281.8
SUPPLEMENTARY INFORMATION
Cash Paid for Interest, Net of Capitalized Amounts	350.2	368.3
Cash Paid (Received) for Transferable Tax Credits	7.1	16.1
Noncash Acquisitions Under Finance Leases	7.9	7.0
Construction Expenditures Included in Current Liabilities as of March 31,	1,040.9	837.0
OPCo
OPERATING ACTIVITIES
Net Income (Loss)	63.0	70.6
Adjustments to Reconcile Net Income to Net Cash Flows from Operating Activities:
Depreciation and Amortization	93.9	105.8
Deferred Income Taxes	1.5	(0.6)
Allowance for Equity Funds Used During Construction	(7.0)	(5.5)
Mark-to-Market of Risk Management Contracts	3.7	(9.7)
Property Taxes	100.8	95.0
Change in Other Noncurrent Assets	50.1	10.1
Change in Other Noncurrent Liabilities	3.0	11.4
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	30.7	(40.2)
Materials and Supplies	7.3	(1.1)
Accounts Payable	(17.2)	(32.4)
Customer Deposits	17.4	14.2
Accrued Taxes, Net	(169.1)	(157.5)
Other Current Assets	5.0	(3.4)
Other Current Liabilities	(17.0)	1.5
Net Cash Flows from Operating Activities	166.1	58.2
INVESTING ACTIVITIES
Construction Expenditures	(253.7)	(241.1)
Change in Advances to Affiliates, Net	114.9	0.0
Other Investing Activities	14.7	5.2
Net Cash Flows Used for Investing Activities	(124.1)	(235.9)
FINANCING ACTIVITIES
Change in Advances from Affiliates, Net	9.7	184.7
Principal Payments for Finance Lease Obligations	(1.2)	(1.3)
Dividends Paid on Common Stock	(46.0)	0.0
Other Financing Activities	0.7	0.4
Net Cash Flows from Financing Activities	(36.8)	183.8
Net Increase (Decrease) in Cash, Cash Equivalents and Restricted Cash	5.2	6.1
Cash, Cash Equivalents and Restricted Cash at Beginning of Period	4.5	6.4
Cash, Cash Equivalents and Restricted Cash at End of Period	9.7	12.5
SUPPLEMENTARY INFORMATION
Cash Paid for Interest, Net of Capitalized Amounts	17.3	19.1
Cash Paid (Received) for Transferable Tax Credits	0.1	0.0
Noncash Acquisitions Under Finance Leases	0.7	0.5
Construction Expenditures Included in Current Liabilities as of March 31,	$ 140.0	$ 104.8