OPERATING SEGMENTS - Reconciliation of Interest and Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Interest and other financial charges	$ 3,273	$ 4,227	$ 4,766
Benefit (provision) for income taxes	474	(726)	(93)
Operating segments | Capital
Segment Reporting Information [Line Items]
Interest and other financial charges	2,186	2,532	2,982
Benefit (provision) for income taxes	862	582	374
Corporate items and eliminations
Segment Reporting Information [Line Items]
Interest and other financial charges	1,087	1,695	1,784
Benefit (provision) for income taxes	$ (388)	$ (1,309)	$ (467)