POSTRETIREMENT BENEFIT PLANS - Composition of Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Jan. 01, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets			$ 18,908
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets			$ 18,908
Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 17,654	$ 19,218
Level 1 | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,258	2,110
Level 2 | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8,091	8,523
Level 3 | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	692	626		$ 61
Level 3 | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	692	626
Net Asset Value | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6,612	7,959
Global equity securities | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,084	3,076
Global equity securities | Level 1 | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	944	1,005
Global equity securities | Level 2 | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	38	1
Global equity securities | Level 3 | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Global equity securities | Net Asset Value | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,101	2,070
Debt securities, cash, and cash equivalents | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	10,593	11,098
Debt securities, cash, and cash equivalents | Level 1 | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,307	1,105
Debt securities, cash, and cash equivalents | Level 2 | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8,000	8,512
Debt securities, cash, and cash equivalents | Level 3 | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt securities, cash, and cash equivalents | Net Asset Value | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,285	1,481
Real estate | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,100	1,420
Real estate | Level 1 | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Real estate | Level 2 | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Real estate | Level 3 | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	476	402
Real estate | Net Asset Value | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	623	1,018
Private equities and other investments | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,877	3,624
Private equities and other investments | Level 1 | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7	0
Private equities and other investments | Level 2 | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	53	10
Private equities and other investments | Level 3 | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	216	224
Private equities and other investments | Net Asset Value | Pension Plans | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 1,602	$ 3,390