Fair Value - Carrying Value and Estimated Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Financial Assets:
Cash and due from banks	$ 2,748	$ 3,631
Interest-bearing deposits with banks	99,199	106,358
Securities purchased under resale agreements	1,308	3,012
Investment securities held-to-maturity	58,320	42,271
Financial Liabilities:
Non-interest-bearing	55,894	56,461
Interest-bearing - U.S.	105,021	102,985
Interest-bearing - non-U.S.	77,321	95,589
Securities sold under repurchase agreements	4,250	1,575
Other short-term borrowings	109	128
Pricing Methods with Significant Observable Market Inputs (Level 2)
Financial Liabilities:
Net loans (excluding leases)	0	8
Reported Amount
Financial Assets:
Cash and due from banks	2,748	3,631
Interest-bearing deposits with banks	99,199	106,358
Securities purchased under resale agreements	1,308	3,012
Investment securities held-to-maturity	65,232	42,430
Net loans	36,016	32,445
Other		1
Financial Liabilities:
Non-interest-bearing	55,894	56,461
Interest-bearing - U.S.	105,021	102,985
Interest-bearing - non-U.S.	77,321	95,589
Securities sold under repurchase agreements	4,250	1,575
Other short-term borrowings	109	128
Long-term debt	13,999	13,475
Other		1
Estimated Fair Value
Financial Assets:
Cash and due from banks	2,748	3,631
Interest-bearing deposits with banks	99,199	106,358
Securities purchased under resale agreements	1,308	3,012
Investment securities held-to-maturity	58,320	42,271
Net loans	35,746	32,528
Other		1
Financial Liabilities:
Non-interest-bearing	55,894	56,461
Interest-bearing - U.S.	105,021	102,985
Interest-bearing - non-U.S.	77,321	95,589
Securities sold under repurchase agreements	4,250	1,575
Other short-term borrowings	109	128
Long-term debt	13,069	13,552
Other		1
Estimated Fair Value | Quoted Market Prices in Active Markets (Level 1)
Financial Assets:
Cash and due from banks	2,748	3,631
Interest-bearing deposits with banks	0	0
Securities purchased under resale agreements	0	0
Investment securities held-to-maturity	11,268	2,160
Net loans	0	0
Other		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
Other short-term borrowings	0	0
Long-term debt	0	0
Other		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	99,199	106,358
Securities purchased under resale agreements	1,308	3,012
Investment securities held-to-maturity	47,052	40,111
Net loans	33,481	29,862
Other		1
Financial Liabilities:
Non-interest-bearing	55,894	56,461
Interest-bearing - U.S.	105,021	102,985
Interest-bearing - non-U.S.	77,321	95,589
Securities sold under repurchase agreements	4,250	1,575
Other short-term borrowings	109	128
Long-term debt	12,913	13,385
Other		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	2,265	2,666
Other		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
Other short-term borrowings	0	0
Long-term debt	$ 156	167
Other		$ 0