SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF PARENT COMPANY - CONDENSED BALANCE SHEETS (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
CURRENT ASSETS
Cash and Cash Equivalents	$ 202.9	$ 330.1
Other Temporary Investments	215.4	214.3
Accounts Receivable:
General	64.1	48.7
Total Accounts Receivable	2,631.9	2,447.4
Accrued Tax Benefits	38.2	156.2
Prepayments and Other Current Assets	285.9	274.2
TOTAL CURRENT ASSETS	5,788.8	6,082.1
PROPERTY, PLANT AND EQUIPMENT
Other Property, Plant and Equipment	7,491.6	6,484.9
Total Property, Plant and Equipment	108,602.0	101,246.4
Accumulated Depreciation and Amortization	26,186.4	24,553.0
TOTAL PROPERTY, PLANT AND EQUIPMENT – NET	82,415.6	76,693.4
OTHER NONCURRENT ASSETS
Deferred Charges and Other Noncurrent Assets	3,873.3	3,625.7
TOTAL OTHER NONCURRENT ASSETS	14,873.6	13,908.5
TOTAL ASSETS	103,078.0	96,684.0
Accounts Payable:
Accounts Payable	2,637.6	2,032.5
Short-term Debt	2,523.8	2,830.2
Long-term Debt Due Within One Year – Nonaffiliated	3,335.0	2,490.5
Other Current Liabilities	1,490.9	1,251.1
TOTAL CURRENT LIABILITIES	13,009.3	11,583.6
NONCURRENT LIABILITIES
Long-term Debt	39,307.8	37,652.7
Deferred Credits and Other Noncurrent Liabilities	800.6	545.8
TOTAL NONCURRENT LIABILITIES	63,044.8	59,772.0
TOTAL LIABILITIES	76,054.1	71,355.6
MEZZANINE EQUITY
Contingently Redeemable Performance Share Awards	37.8	42.5
COMMON SHAREHOLDER’S EQUITY
Common Stock	3,471.6	3,427.9
Paid-in Capital	9,606.1	9,073.9
Retained Earnings	13,869.2	12,800.4
Accumulated Other Comprehensive Income (Loss)	(3.1)	(55.5)
TOTAL COMMON SHAREHOLDER’S EQUITY	26,943.8	25,246.7
TOTAL LIABILITIES, MEZZANINE EQUITY AND EQUITY	103,078.0	96,684.0
Parent Company
CURRENT ASSETS
Cash and Cash Equivalents	87.5	197.8
Other Temporary Investments	2.9	2.6
Advances to Affiliates	1,944.6	2,004.5
Accounts Receivable:
General	0.0	2.7
Total Accounts Receivable	32.5	50.4
Accrued Tax Benefits	93.7	77.7
Prepayments and Other Current Assets	11.6	11.6
TOTAL CURRENT ASSETS	2,172.8	2,344.6
PROPERTY, PLANT AND EQUIPMENT
Other Property, Plant and Equipment	3.2	3.1
Total Property, Plant and Equipment	3.2	3.1
Accumulated Depreciation and Amortization	1.7	1.4
TOTAL PROPERTY, PLANT AND EQUIPMENT – NET	1.5	1.7
OTHER NONCURRENT ASSETS
Investments in Unconsolidated Subsidiaries	35,306.2	33,598.6
Affiliated Notes Receivable	105.0	295.0
Deferred Charges and Other Noncurrent Assets	184.6	137.0
TOTAL OTHER NONCURRENT ASSETS	35,595.8	34,030.6
TOTAL ASSETS	37,770.1	36,376.9
CURRENT LIABILITIES
Advances from Affiliates	506.6	728.3
Accounts Payable:
Short-term Debt	1,618.3	1,937.9
Long-term Debt Due Within One Year – Nonaffiliated	1,281.5	1,104.0
Other Current Liabilities	202.4	137.7
TOTAL CURRENT LIABILITIES	3,615.7	3,931.3
NONCURRENT LIABILITIES
Long-term Debt	7,124.3	7,086.9
Deferred Credits and Other Noncurrent Liabilities	48.5	69.5
TOTAL NONCURRENT LIABILITIES	7,172.8	7,156.4
TOTAL LIABILITIES	10,788.5	11,087.7
MEZZANINE EQUITY
Contingently Redeemable Performance Share Awards	37.8	42.5
COMMON SHAREHOLDER’S EQUITY
Common Stock	3,471.6	3,427.9
Paid-in Capital	9,606.1	9,073.9
Retained Earnings	13,869.2	12,800.4
Accumulated Other Comprehensive Income (Loss)	(3.1)	(55.5)
TOTAL COMMON SHAREHOLDER’S EQUITY	26,943.8	25,246.7
TOTAL LIABILITIES, MEZZANINE EQUITY AND EQUITY	37,770.1	36,376.9
Parent Company | Nonrelated Party
Accounts Payable:
Accounts Payable	4.7	11.1
Parent Company | Affiliated Entity
Accounts Receivable:
Affiliated Companies	32.5	47.7
Accounts Payable:
Accounts Payable	$ 2.2	$ 12.3