ALL OTHER ASSETS - Equity Method Investments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Entity Information [Line Items]
Equity method investment balance	$ 7,391	$ 6,100
Equity method income (loss)	215	46	$ 265
Operating segments | Aviation
Entity Information [Line Items]
Equity method investment balance	2,000	2,032
Equity method income (loss)	58	(41)	204
Operating segments | Healthcare
Entity Information [Line Items]
Equity method investment balance	223	251
Equity method income (loss)	27	7	19
Operating segments | Renewable Energy
Entity Information [Line Items]
Equity method investment balance	739	724
Equity method income (loss)	39	13	(2)
Operating segments | Power
Entity Information [Line Items]
Equity method investment balance	977	576
Equity method income (loss)	23	43	(4)
Corporate
Entity Information [Line Items]
Equity method investment balance	3,451	2,517
Equity method income (loss)	68	23	$ 48
Corporate | EFS
Entity Information [Line Items]
Equity method investment balance	1,943	1,816
Corporate | Insurance
Entity Information [Line Items]
Equity method investment balance	$ 1,480	$ 669