PLEDGED ASSETS, RESTRICTED CASH, COLLATERAL, GUARANTEES AND COMMITMENTS - Credit Commitments and Lines of Credit (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Credit Commitments
Credit commitments	$ 1,021,802	$ 1,015,564
Unsettled reverse repurchase and securities borrowing agreements	120,900	111,600
Unsettled repurchase and securities lending agreements	96,400	37,300
Commercial and similar letters of credit
Credit Commitments
Credit commitments	5,345	5,316
One-to four-family residential mortgages
Credit Commitments
Credit commitments	1,245	2,394
Revolving open-end loans secured by one-to four-family residential properties
Credit Commitments
Credit commitments	5,495	6,380
Commercial real estate, construction and land development
Credit Commitments
Credit commitments	15,266	15,170
Credit card lines
Credit Commitments
Credit commitments	677,005	683,232
Commercial and other consumer loan commitments
Credit Commitments
Credit commitments	312,300	297,399
Other commitments and contingencies
Credit Commitments
Credit commitments	5,146	5,673
U.S.
Credit Commitments
Credit commitments	841,615
U.S. | Commercial and similar letters of credit
Credit Commitments
Credit commitments	942
U.S. | One-to four-family residential mortgages
Credit Commitments
Credit commitments	638
U.S. | Revolving open-end loans secured by one-to four-family residential properties
Credit Commitments
Credit commitments	5,471
U.S. | Commercial real estate, construction and land development
Credit Commitments
Credit commitments	13,629
U.S. | Credit card lines
Credit Commitments
Credit commitments	612,101
U.S. | Commercial and other consumer loan commitments
Credit Commitments
Credit commitments	203,851
U.S. | Other commitments and contingencies
Credit Commitments
Credit commitments	4,983
U.S. | Other commitments and contingencies | Federal Reserve Bank Stock
Credit Commitments
Credit commitments	4,500	$ 4,500
Outside U.S.
Credit Commitments
Credit commitments	180,187
Outside U.S. | Commercial and similar letters of credit
Credit Commitments
Credit commitments	4,403
Outside U.S. | One-to four-family residential mortgages
Credit Commitments
Credit commitments	607
Outside U.S. | Revolving open-end loans secured by one-to four-family residential properties
Credit Commitments
Credit commitments	24
Outside U.S. | Commercial real estate, construction and land development
Credit Commitments
Credit commitments	1,637
Outside U.S. | Credit card lines
Credit Commitments
Credit commitments	64,904
Outside U.S. | Commercial and other consumer loan commitments
Credit Commitments
Credit commitments	108,449
Outside U.S. | Other commitments and contingencies
Credit Commitments
Credit commitments	$ 163