PARENT COMPANY FINANCIALS - Condensed Statements of Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
OPERATING INCOME:
Total interest income	$ 10,204	$ 7,060	$ 4,851
OPERATING EXPENSE:
Salaries and employee benefits	2,599	2,549	2,132
Interest expense	3,963	1,048	339
All other expenses	973	585	411
Income tax expense (benefit)	422	582	658
NET INCOME	1,608	2,073	2,319
Total other comprehensive income (loss), net of income taxes	802	(3,895)	(605)
Total comprehensive income (loss)	2,410	(1,822)	1,714
Parent company
OPERATING INCOME:
Dividends	2,875	450	1,120
Interest	43	39	35
Management and service fees	69	69	64
All other operating income	1	1	1
Total interest income	2,996	605	1,279
OPERATING EXPENSE:
Salaries and employee benefits	39	43	36
Interest expense	129	125	119
All other expenses	31	28	28
Total operating expense	199	196	183
Income before income tax expense	2,797	409	1,096
Income tax expense (benefit)	(13)	(13)	(16)
Income before undistributed income of subsidiaries	2,810	422	1,112
NET INCOME	1,608	2,073	2,319
Total other comprehensive income (loss), net of income taxes	802	(3,895)	(605)
Total comprehensive income (loss)	2,410	(1,822)	1,714
Nonbank subsidiaries | Parent company
OPERATING INCOME:
Interest	8	3	2
Dividends	0	43	57
OPERATING EXPENSE:
Equity in undistributed income (losses) of subsidiaries	(39)	(73)	19
Bank subsidiaries | Parent company
OPERATING EXPENSE:
Equity in undistributed income (losses) of subsidiaries	$ (1,163)	$ 1,724	$ 1,188