GUARANTEES AND COMMITMENTS - Credit Commitments and Lines of Credit (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Guarantor Obligations
Credit commitments	$ 1,026,657	$ 1,015,564
Unsettled reverse repurchase and securities borrowing agreements	143,900	111,600
Unsettled repurchase and securities lending agreements	108,700	37,300
Commercial and similar letters of credit
Guarantor Obligations
Credit commitments	5,208	5,316
One- to four-family residential mortgages
Guarantor Obligations
Credit commitments	1,443	2,394
Revolving open-end loans secured by one- to four-family residential properties
Guarantor Obligations
Credit commitments	5,578	6,380
Commercial real estate, construction and land development
Guarantor Obligations
Credit commitments	15,496	15,170
Credit card lines
Guarantor Obligations
Credit commitments	678,994	683,232
Commercial and other consumer loan commitments
Guarantor Obligations
Credit commitments	314,452	297,399
Other commitments and contingencies(2)
Guarantor Obligations
Credit commitments	5,486	5,673
U.S.
Guarantor Obligations
Credit commitments	846,084
U.S. | Commercial and similar letters of credit
Guarantor Obligations
Credit commitments	659
U.S. | One- to four-family residential mortgages
Guarantor Obligations
Credit commitments	756
U.S. | Revolving open-end loans secured by one- to four-family residential properties
Guarantor Obligations
Credit commitments	5,553
U.S. | Commercial real estate, construction and land development
Guarantor Obligations
Credit commitments	13,451
U.S. | Credit card lines
Guarantor Obligations
Credit commitments	614,535
U.S. | Commercial and other consumer loan commitments
Guarantor Obligations
Credit commitments	205,749
U.S. | Other commitments and contingencies(2)
Guarantor Obligations
Credit commitments	5,381
U.S. | Other commitments and contingencies(2) | Federal Reserve Bank Stock
Guarantor Obligations
Credit commitments	4,500	$ 4,500
In offices outside North America
Guarantor Obligations
Credit commitments	180,573
In offices outside North America | Commercial and similar letters of credit
Guarantor Obligations
Credit commitments	4,549
In offices outside North America | One- to four-family residential mortgages
Guarantor Obligations
Credit commitments	687
In offices outside North America | Revolving open-end loans secured by one- to four-family residential properties
Guarantor Obligations
Credit commitments	25
In offices outside North America | Commercial real estate, construction and land development
Guarantor Obligations
Credit commitments	2,045
In offices outside North America | Credit card lines
Guarantor Obligations
Credit commitments	64,459
In offices outside North America | Commercial and other consumer loan commitments
Guarantor Obligations
Credit commitments	108,703
In offices outside North America | Other commitments and contingencies(2)
Guarantor Obligations
Credit commitments	$ 105