TAXES - Reconciliation of Federal Income Tax Expense (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	May 31, 2022
Reconciliation of federal income tax expense at the federal statutory rate to the total provision for income taxes
Income from continuing operations, before income taxes			$ 1,464	$ 1,439	$ 1,559
Federal income tax expense at the 21% statutory rate			307	302	327
Increases (reductions) in taxes resulting from-
State and municipal income taxes, net of federal tax benefit			80	56	122
AFUDC equity and other flow-through			(30)	(26)	(29)
Amortization of investment tax credits			(3)	(4)	(4)
Deferred gain on 19.9% FET minority interest sale			58	752	0
Federal tax credits claimed			(3)	(3)	(34)
Nondeductible DPA monetary penalty			0	0	52
Excess deferred tax amortization due to the Tax Act			(46)	(51)	(54)
Uncertain tax positions			41	2	(82)
Valuation allowances	$ 37		(146)	(47)	17
Other, net			9	19	5
Total income taxes on income from continuing operations		$ 65	$ 267	$ 1,000	$ 320
Effective income tax rate (percent)			18.20%	69.50%	20.50%
Brookfield II | FET
Provision for Income Tax [Line Items]
Sale of ownership interest by parent	19.90%		19.90%			19.90%