INCOME TAXES - Schedule of Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Income before income taxes	$ 560	$ 470	$ 1,125	$ 1,198
Federal income tax expense at statutory rate (21%)	118	99	236	252
Increases (reductions) in tax expense resulting from:
State and municipal income taxes, net of federal tax benefit	33	25	76	49
AFUDC equity and other flow-through	(6)	(15)	(19)	(25)
Deductions associated with certain equity method investments	(14)	0	(14)	0
Deferred taxes related to sale of equity interest in FET, net	0	0	7	0
Excess deferred tax amortization due to the Tax Act	(13)	2	(40)	(30)
Federal tax credits claimed	0	(2)	0	(2)
Nondeductible SEC and OOCIC settlements	0	0	27	0
Remeasurement of excess deferred taxes	(21)	0	(21)	0
Uncertain tax positions	0	50	0	50
Valuation allowances	(3)	(122)	33	(113)
Other, net	0	(8)	9	12
Total income taxes	$ 94	$ 29	$ 294	$ 193
Effective income tax rate	16.80%	6.20%	26.10%	16.10%