PENSION AND OTHER POST-EMPLOYMENT BENEFITS - Obligations and Funded Status (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Pension
Change in benefit obligation:
Benefit obligation as of January 1	$ 11,479	$ 11,935
Service cost	184	195	$ 194
Interest cost	273	226	287
Plan participants’ contributions	0	0
Medicare retiree drug subsidy	0	0
Actuarial loss (gain)	(2,515)	(280)
Benefits paid	(593)	(597)
Benefit obligation as of December 31	8,828	11,479	11,935
Change in fair value of plan assets:
Fair value of plan assets as of January 1	9,020	8,968
Actual return on plan assets	(1,760)	625
Company contributions	26	24
Plan participants’ contributions	0	0
Benefits paid	(593)	(597)
Fair value of plan assets as of December 31	6,693	9,020	8,968
Funded Status:
Funded Status (Net liability as of December 31)	(2,135)	(2,459)
Accumulated benefit obligation	8,500	10,927
Amounts Recognized in AOCI:
Prior service cost (credit)	6	9
Pension \| Qualified plan
Funded Status:
Funded Status (Net liability as of December 31)	(1,734)	(1,974)
Pension \| Non-qualified plans
Funded Status:
Funded Status (Net liability as of December 31)	(401)	(485)
OPEB
Change in benefit obligation:
Benefit obligation as of January 1	549	676
Service cost	3	4	4
Interest cost	11	11	15
Plan participants’ contributions	3	4
Medicare retiree drug subsidy	1	1
Actuarial loss (gain)	(83)	(101)
Benefits paid	(45)	(46)
Benefit obligation as of December 31	439	549	676
Change in fair value of plan assets:
Fair value of plan assets as of January 1	548	502
Actual return on plan assets	(70)	64
Company contributions	24	24
Plan participants’ contributions	3	4
Benefits paid	(45)	(46)
Fair value of plan assets as of December 31	460	548	$ 502
Funded Status:
Funded Status (Net liability as of December 31)	21	(1)
Accumulated benefit obligation	0	0
Amounts Recognized in AOCI:
Prior service cost (credit)	(10)	(21)
OPEB \| Qualified plan
Funded Status:
Funded Status (Net liability as of December 31)	0	0
OPEB \| Non-qualified plans
Funded Status:
Funded Status (Net liability as of December 31)	$ 0	$ 0

Amount of actuarial present value of benefits attributed to employee service rendered, excluding assumptions about future compensation level.

Name:	us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, before tax, of accumulated other comprehensive (income) loss for cost (credit) of benefit change attributable to participants' prior service from plan amendment or plan initiation of defined benefit plan, that has not been recognized in net periodic benefit cost (credit).