Commitments, Contingencies, Guarantees, and Others - Unfunded Lending Commitments: Contractual Amount and Carrying Value (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Loss Contingencies [Line Items]
Unfunded lending commitments, contractual amount	$ 439,198	$ 409,314
Off-balance sheet lending commitment, carrying value	125	204
Credit Card:
Loss Contingencies [Line Items]
Unused commitments to extend credit, contractual amount	390,477	359,507
Other excluding credit card
Loss Contingencies [Line Items]
Unused commitments to extend credit, contractual amount	47,280	48,405
Off-balance sheet lending commitment, carrying value	102	176
Advised line of credit	5,100	4,400
Letter of credit
Loss Contingencies [Line Items]
Standby letters of credit and commercial letters of credit, contractual amount	1,441	1,402
Off-balance sheet lending commitment, carrying value	$ 23	$ 28