PARENT COMPANY FINANCIALS - Condensed Statements of Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
OPERATING INCOME:
Total interest income	$ 10,186	$ 10,204	$ 7,060
OPERATING EXPENSE:
Salaries and employee benefits	2,657	2,599	2,549
Interest expense	4,553	3,963	1,048
All other expenses	722	973	585
Income tax expense (benefit)	379	422	582
NET INCOME	1,509	1,608	2,073
Total other comprehensive income (loss), net of income taxes	163	802	(3,895)
Total comprehensive income (loss)	1,672	2,410	(1,822)
Parent company
OPERATING INCOME:
Dividends	625	2,875	450
Interest	139	43	39
Management and service fees	67	69	69
All other operating income	1	1	1
Total interest income	841	2,996	605
OPERATING EXPENSE:
Salaries and employee benefits	36	39	43
Interest expense	263	129	125
All other expenses	32	31	28
Total operating expense	331	199	196
Income before income tax expense	510	2,797	409
Income tax expense (benefit)	(24)	(13)	(13)
Income before undistributed income of subsidiaries	534	2,810	422
NET INCOME	1,509	1,608	2,073
Total other comprehensive income (loss), net of income taxes	163	802	(3,895)
Total comprehensive income (loss)	1,672	2,410	(1,822)
Nonbank subsidiaries | Parent company
OPERATING INCOME:
Interest	9	8	3
Dividends	0	0	43
OPERATING EXPENSE:
Equity in undistributed income (losses) of subsidiaries	36	(39)	(73)
Bank subsidiaries | Parent company
OPERATING EXPENSE:
Equity in undistributed income (losses) of subsidiaries	$ 939	$ (1,163)	$ 1,724