OTHER ASSETS - Schedule of Other Assets (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Equity method investments	$ 451	$ 459
Other investments	450	52
Post-retirement plan assets	44	38
Other	113	69
Total other assets	$ 1,058	$ 618