PENSION AND OTHER POST-EMPLOYMENT BENEFITS - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Increase in discount rate		2.21%
Pension
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets		7.50%	7.50%	7.50%
Expected future contributions in 2025		$ 250
Expected return on plan assets		657	$ 652	$ 618
Actual return on plan assets		(1,760)	625
Increase in benefit obligation due to RP2014 mortality table		23
Pension | Forecast
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets	8.00%
Pensions and OPEB
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets		696	688	651
Actual return on plan assets		$ (1,830)	$ 689	$ 1,225
Actual return on plan assets (percent)		(19.10%)	7.90%	14.70%
OPEB
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets		7.50%	7.50%	7.50%
Expected return on plan assets		$ 39	$ 36	$ 33
Actual return on plan assets		(70)	64
OPEB | Regulated Transmission
Defined Benefit Plan Disclosure [Line Items]
Mark-to-market adjustment, net of capitalized amounts		$ 15	$ (31)	$ 40