ACCUMULATED OTHER COMPREHENSIVE INCOME - Summary of Changes in AOCI by Component (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Gains (losses)
Balance, beginning of period (in usd)	$ 9,121	$ 8,726
Other comprehensive income (loss) before reclassifications	(13)	(192)
Amounts reclassified from AOCI	6	26
Net other comprehensive income (loss)	(7)	(166)
Balance, end of period (in usd)	9,119	8,490
CTA
Gains (losses)
Balance, beginning of period (in usd)	(2,907)	(2,587)
Other comprehensive income (loss) before reclassifications	(15)	(208)
Amounts reclassified from AOCI	0	0
Net other comprehensive income (loss)	(15)	(208)
Balance, end of period (in usd)	(2,922)	(2,795)
Pension and OPEB plans
Gains (losses)
Balance, beginning of period (in usd)	(347)	(574)
Other comprehensive income (loss) before reclassifications	2	13
Amounts reclassified from AOCI	7	17
Net other comprehensive income (loss)	9	30
Balance, end of period (in usd)	(338)	(544)
Hedging activities
Gains (losses)
Balance, beginning of period (in usd)	(126)	(153)
Other comprehensive income (loss) before reclassifications	(1)	3
Amounts reclassified from AOCI	(1)	9
Net other comprehensive income (loss)	(2)	12
Balance, end of period (in usd)	(128)	(141)
Debt securities
Gains (losses)
Balance, beginning of period (in usd)	0
Other comprehensive income (loss) before reclassifications	1
Amounts reclassified from AOCI	0
Net other comprehensive income (loss)	1
Balance, end of period (in usd)	1
Total
Gains (losses)
Balance, beginning of period (in usd)	(3,380)	(3,314)
Balance, end of period (in usd)	$ (3,387)	$ (3,480)