Fair Value - Carrying Value and Estimated Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Financial Assets:
Cash and due from banks	$ 3,970	$ 3,631
Interest-bearing deposits with banks	101,593	106,358
Securities purchased under resale agreements	5,215	3,012
Investment securities held-to-maturity	57,913	42,271
Financial Liabilities:
Non-interest-bearing	46,755	56,461
Interest-bearing - U.S.	111,384	102,985
Interest-bearing - non-U.S.	77,325	95,589
Securities sold under repurchase agreements	1,177	1,575
Short-term borrowings	2,097	128
Pricing Methods with Significant Observable Market Inputs (Level 2)
Financial Assets:
Net loans (excluding leases)	5	8
Reported Amount
Financial Assets:
Cash and due from banks	3,970	3,631
Interest-bearing deposits with banks	101,593	106,358
Securities purchased under resale agreements	5,215	3,012
Investment securities held-to-maturity	64,700	42,430
Net loans (excluding leases)	32,053	32,445
Other	3,626	1
Financial Liabilities:
Non-interest-bearing	46,755	56,461
Interest-bearing - U.S.	111,384	102,985
Interest-bearing - non-U.S.	77,325	95,589
Securities sold under repurchase agreements	1,177	1,575
Short-term borrowings	2,097	128
Long-term debt	14,996	13,475
Other	3,626	1
Estimated Fair Value
Financial Assets:
Cash and due from banks	3,970	3,631
Interest-bearing deposits with banks	101,593	106,358
Securities purchased under resale agreements	5,215	3,012
Investment securities held-to-maturity	57,913	42,271
Net loans (excluding leases)	31,794	32,528
Other	3,626	1
Financial Liabilities:
Non-interest-bearing	46,755	56,461
Interest-bearing - U.S.	111,384	102,985
Interest-bearing - non-U.S.	77,325	95,589
Securities sold under repurchase agreements	1,177	1,575
Short-term borrowings	2,097	128
Long-term debt	14,273	13,552
Other	3,626	1
Estimated Fair Value | Quoted Market Prices in Active Markets (Level 1)
Financial Assets:
Cash and due from banks	3,970	3,631
Interest-bearing deposits with banks	0	0
Securities purchased under resale agreements	0	0
Investment securities held-to-maturity	11,336	2,160
Net loans (excluding leases)	0	0
Other	0	0
Financial Liabilities:
Non-interest-bearing	0	0
Interest-bearing - U.S.	0	0
Interest-bearing - non-U.S.	0	0
Securities sold under repurchase agreements	0	0
Short-term borrowings	0	0
Long-term debt	0	0
Other	0	0
Estimated Fair Value | Pricing Methods with Significant Observable Market Inputs (Level 2)
Financial Assets:
Cash and due from banks	0	0
Interest-bearing deposits with banks	101,593	106,358
Securities purchased under resale agreements	5,215	3,012
Investment securities held-to-maturity	46,577	40,111
Net loans (excluding leases)	29,679	29,862
Other	3,626	1
Financial Liabilities:
Non-interest-bearing	46,755	56,461
Interest-bearing - U.S.	111,384	102,985
Interest-bearing - non-U.S.	77,325	95,589
Securities sold under repurchase agreements	1,177	1,575
Short-term borrowings	2,097	128
Long-term debt	14,102	13,385
Other	3,626	1
Estimated Fair Value | Pricing Methods with Significant Unobservable Market Inputs (Level 3)
Financial Assets:
Cash and due from banks	0	0
Interest-bearing deposits with banks	0	0
Securities purchased under resale agreements	0	0
Investment securities held-to-maturity	0	0
Net loans (excluding leases)	2,115	2,666
Other	0	0
Financial Liabilities:
Non-interest-bearing	0	0
Interest-bearing - U.S.	0	0
Interest-bearing - non-U.S.	0	0
Securities sold under repurchase agreements	0	0
Short-term borrowings	0	0
Long-term debt	171	167
Other	$ 0	$ 0