Fair Value - Carrying Value and Estimated Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Financial Assets:
Cash and due from banks	$ 3,698	$ 3,970
Interest-bearing deposits with banks (less allowance for credit losses of $29 and $0)	87,935	101,593
Securities purchased under resale agreements	1,134	5,215
Investment securities held-to-maturity	59,139	57,913
Financial Liabilities:
Non-interest-bearing	45,856	46,755
Interest-bearing - U.S.	108,623	111,384
Interest-bearing - non-U.S.	69,152	77,325
Securities sold under repurchase agreements	3,695	1,177
Short-term borrowings	8	2,097
Pricing Methods with Significant Observable Market Inputs (Level 2)
Financial Liabilities:
Net loans (excluding leases)	12	5
Reported Amount
Financial Assets:
Cash and due from banks	3,698	3,970
Interest-bearing deposits with banks (less allowance for credit losses of $29 and $0)	87,935	101,593
Securities purchased under resale agreements	1,134	5,215
Investment securities held-to-maturity	65,027	64,700
Net loans	33,801	32,053
Other	3,626	3,626
Financial Liabilities:
Non-interest-bearing	45,856	46,755
Interest-bearing - U.S.	108,623	111,384
Interest-bearing - non-U.S.	69,152	77,325
Securities sold under repurchase agreements	3,695	1,177
Short-term borrowings	8	2,097
Long-term debt	16,305	14,996
Other	3,626	3,626
Estimated Fair Value
Financial Assets:
Cash and due from banks	3,698	3,970
Interest-bearing deposits with banks (less allowance for credit losses of $29 and $0)	87,935	101,593
Securities purchased under resale agreements	1,134	5,215
Investment securities held-to-maturity	59,139	57,913
Net loans	33,581	31,794
Other	3,626	3,626
Financial Liabilities:
Non-interest-bearing	45,856	46,755
Interest-bearing - U.S.	108,623	111,384
Interest-bearing - non-U.S.	69,152	77,325
Securities sold under repurchase agreements	3,695	1,177
Short-term borrowings	8	2,097
Long-term debt	15,590	14,273
Other	3,626	3,626
Estimated Fair Value | Quoted Market Prices in Active Markets (Level 1)
Financial Assets:
Cash and due from banks	3,698	3,970
Interest-bearing deposits with banks (less allowance for credit losses of $29 and $0)	0	0
Securities purchased under resale agreements	0	0
Investment securities held-to-maturity	11,475	11,336
Net loans	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 (less allowance for credit losses of $29 and $0)	87,935	101,593
Securities purchased under resale agreements	1,134	5,215
Investment securities held-to-maturity	47,664	46,577
Net loans	31,541	29,679
Other	3,626	3,626
Financial Liabilities:
Non-interest-bearing	45,856	46,755
Interest-bearing - U.S.	108,623	111,384
Interest-bearing - non-U.S.	69,152	77,325
Securities sold under repurchase agreements	3,695	1,177
Short-term borrowings	8	2,097
Long-term debt	15,428	14,102
Other	3,626	3,626
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 (less allowance for credit losses of $29 and $0)	0	0
Securities purchased under resale agreements	0	0
Investment securities held-to-maturity	0	0
Net loans	2,040	2,115
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	162	171
Other	$ 0	$ 0