GUARANTEES AND COMMITMENTS - Credit Commitments and Lines of Credit (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Guarantor Obligations
Credit commitments	$ 1,038,677	$ 1,031,362
Unsettled reverse repurchase and securities borrowing agreements	177,100	117,700
Unsettled repurchase and securities lending agreements	174,500	126,800
Commercial and similar letters of credit
Guarantor Obligations
Credit commitments	3,696	4,031
One- to four-family residential mortgages
Guarantor Obligations
Credit commitments	1,201	967
Revolving open-end loans secured by one- to four-family residential properties
Guarantor Obligations
Credit commitments	5,255	5,271
Commercial real estate, construction and land development
Guarantor Obligations
Credit commitments	13,622	14,107
Credit card lines
Guarantor Obligations
Credit commitments	686,739	676,749
Commercial and other consumer loan commitments
Guarantor Obligations
Credit commitments	323,004	325,329
Other commitments and contingencies
Guarantor Obligations
Credit commitments	5,160	4,908
U.S.
Guarantor Obligations
Credit commitments	864,063
U.S. | Commercial and similar letters of credit
Guarantor Obligations
Credit commitments	494
U.S. | One- to four-family residential mortgages
Guarantor Obligations
Credit commitments	670
U.S. | Revolving open-end loans secured by one- to four-family residential properties
Guarantor Obligations
Credit commitments	5,220
U.S. | Commercial real estate, construction and land development
Guarantor Obligations
Credit commitments	11,641
U.S. | Credit card lines
Guarantor Obligations
Credit commitments	626,256
U.S. | Commercial and other consumer loan commitments
Guarantor Obligations
Credit commitments	214,697
U.S. | Other commitments and contingencies
Guarantor Obligations
Credit commitments	5,085
U.S. | Other commitments and contingencies | Federal Reserve Bank Stock
Guarantor Obligations
Credit commitments	4,500	$ 4,500
In offices outside North America
Guarantor Obligations
Credit commitments	174,614
In offices outside North America | Commercial and similar letters of credit
Guarantor Obligations
Credit commitments	3,202
In offices outside North America | One- to four-family residential mortgages
Guarantor Obligations
Credit commitments	531
In offices outside North America | Revolving open-end loans secured by one- to four-family residential properties
Guarantor Obligations
Credit commitments	35
In offices outside North America | Commercial real estate, construction and land development
Guarantor Obligations
Credit commitments	1,981
In offices outside North America | Credit card lines
Guarantor Obligations
Credit commitments	60,483
In offices outside North America | Commercial and other consumer loan commitments
Guarantor Obligations
Credit commitments	108,307
In offices outside North America | Other commitments and contingencies
Guarantor Obligations
Credit commitments	$ 75