OTHER ASSETS - Schedule of Other Assets (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Equity method investments	$ 498	$ 451
Other investments	608	450
Post-retirement plan assets	50	44
Other	117	113
Total other assets	$ 1,273	$ 1,058