GUARANTEES AND COMMITMENTS - Credit Commitments and Lines of Credit (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Guarantor Obligations
Credit commitments	$ 1,030,716	$ 1,021,802
Unsettled reverse repurchase and securities borrowing agreements	160,300	120,900
Unsettled repurchase and securities lending agreements	150,200	96,400
Commercial and similar letters of credit
Guarantor Obligations
Credit commitments	4,415	5,345
One- to four-family residential mortgages
Guarantor Obligations
Credit commitments	1,187	1,245
Revolving open-end loans secured by one- to four-family residential properties
Guarantor Obligations
Credit commitments	5,351	5,495
Commercial real estate, construction and land development
Guarantor Obligations
Credit commitments	13,311	15,266
Credit card lines
Guarantor Obligations
Credit commitments	678,629	677,005
Commercial and other consumer loan commitments
Guarantor Obligations
Credit commitments	322,746	312,300
Other commitments and contingencies(2)
Guarantor Obligations
Credit commitments	5,077	5,146
U.S.
Guarantor Obligations
Credit commitments	856,277
U.S. | Commercial and similar letters of credit
Guarantor Obligations
Credit commitments	674
U.S. | One- to four-family residential mortgages
Guarantor Obligations
Credit commitments	607
U.S. | Revolving open-end loans secured by one- to four-family residential properties
Guarantor Obligations
Credit commitments	5,332
U.S. | Commercial real estate, construction and land development
Guarantor Obligations
Credit commitments	11,673
U.S. | Credit card lines
Guarantor Obligations
Credit commitments	617,155
U.S. | Commercial and other consumer loan commitments
Guarantor Obligations
Credit commitments	215,894
U.S. | Other commitments and contingencies(2)
Guarantor Obligations
Credit commitments	4,942
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	174,439
In offices outside North America | Commercial and similar letters of credit
Guarantor Obligations
Credit commitments	3,741
In offices outside North America | One- to four-family residential mortgages
Guarantor Obligations
Credit commitments	580
In offices outside North America | Revolving open-end loans secured by one- to four-family residential properties
Guarantor Obligations
Credit commitments	19
In offices outside North America | Commercial real estate, construction and land development
Guarantor Obligations
Credit commitments	1,638
In offices outside North America | Credit card lines
Guarantor Obligations
Credit commitments	61,474
In offices outside North America | Commercial and other consumer loan commitments
Guarantor Obligations
Credit commitments	106,852
In offices outside North America | Other commitments and contingencies(2)
Guarantor Obligations
Credit commitments	$ 135