Commitments, Contingencies, Guarantees and Others - Unfunded Lending Commitments: Contractual Amount and Carrying Value (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Loss Contingencies [Line Items]
Total unfunded lending commitments, contractual amount	$ 459,213	$ 441,283
Off-balance sheet lending commitment, carrying value	93	122
Credit Card:
Loss Contingencies [Line Items]
Credit car lines, contractual amount	412,030	392,867
Other loan commitments
Loss Contingencies [Line Items]
Credit car lines, contractual amount	45,823	46,951
Off-balance sheet lending commitment, carrying value	68	99
Advised line of credit	5,300	4,700
Letter of credit
Loss Contingencies [Line Items]
Standby letters of credit and commercial letters of credit, contractual amount	1,360	1,465
Off-balance sheet lending commitment, carrying value	$ 25	$ 23