RETIREMENT AND POSTRETIREMENT BENEFIT PLANS - FAIR VALUE OF PENSION PLAN ASSETS (Details) - Pension Benefits - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure
Fair value of plan assets, net of net payables	$ 1,196	$ 1,844
Cash and cash equivalents
Defined Benefit Plan Disclosure
Fair value of plan assets	38	42
Government securities
Defined Benefit Plan Disclosure
Fair value of plan assets	65	63
Corporate bonds
Defined Benefit Plan Disclosure
Fair value of plan assets	39	94
Equity securities
Defined Benefit Plan Disclosure
Fair value of plan assets	138	311
Other
Defined Benefit Plan Disclosure
Fair value of plan assets	55	81
Net payables
Defined Benefit Plan Disclosure
Fair value of plan assets	3	3
Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure
Fair value of plan assets	335	591
Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	241	416
Fair value of plan assets, net of net payables	241	416
Level 1 | Cash and cash equivalents
Defined Benefit Plan Disclosure
Fair value of plan assets	38	42
Level 1 | Government securities
Defined Benefit Plan Disclosure
Fair value of plan assets	65	63
Level 1 | Corporate bonds
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Level 1 | Equity securities
Defined Benefit Plan Disclosure
Fair value of plan assets	138	311
Level 1 | Other
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	94	175
Fair value of plan assets, net of net payables	94	175
Level 2 | Cash and cash equivalents
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Level 2 | Government securities
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Level 2 | Corporate bonds
Defined Benefit Plan Disclosure
Fair value of plan assets	39	94
Level 2 | Equity securities
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Level 2 | Other
Defined Benefit Plan Disclosure
Fair value of plan assets	55	81
Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Fair value of plan assets, net of net payables	0	0
Level 3 | Cash and cash equivalents
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Level 3 | Government securities
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Level 3 | Corporate bonds
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Level 3 | Equity securities
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Level 3 | Other
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Investments measured at net asset value
Defined Benefit Plan Disclosure
Fair value of plan assets	$ 861	$ 1,253