Variable Interest Entities and Securitizations - Carrying Amount of Consolidated and Unconsolidated VIEs (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Variable Interest Entity [Line Items]
Carrying Amount of Assets	$ 480,018	$ 478,464
Carrying Amount of Liabilities	422,037	420,375
Maximum Exposure to Loss	6,003	6,175
Consolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	33,401	33,288
Carrying Amount of Liabilities	17,991	18,746
Unconsolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	6,003	6,175
Carrying Amount of Liabilities	2,003	2,085
Affordable housing entities
Variable Interest Entity [Line Items]
Maximum Exposure to Loss	5,603	5,726
VIE, nonconsolidated, carrying amount of assets included in certain investment structures	2,700	2,600
VIE, nonconsolidated, carrying amount of liabilities included in certain investment structures	1,000	989
Affordable housing entities | Consolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	356	297
Carrying Amount of Liabilities	75	23
Affordable housing entities | Unconsolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	5,603	5,726
Carrying Amount of Liabilities	1,995	2,085
Entities that provide capital to low-income and rural communities
Variable Interest Entity [Line Items]
Maximum Exposure to Loss	0	0
Entities that provide capital to low-income and rural communities | Consolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	2,745	2,498
Carrying Amount of Liabilities	10	10
Entities that provide capital to low-income and rural communities | Unconsolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	0	0
Carrying Amount of Liabilities	0	0
Other
Variable Interest Entity [Line Items]
Maximum Exposure to Loss	400	449
Other | Consolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	0	0
Carrying Amount of Liabilities	0	0
Other | Unconsolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	400	449
Carrying Amount of Liabilities	8	0
Total other VIEs
Variable Interest Entity [Line Items]
Maximum Exposure to Loss	6,003	6,175
Total other VIEs | Consolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	3,101	2,795
Carrying Amount of Liabilities	85	33
Total other VIEs | Unconsolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	6,003	6,175
Carrying Amount of Liabilities	2,003	2,085
Credit card loan securitizations
Variable Interest Entity [Line Items]
Maximum Exposure to Loss	0	0
Credit card loan securitizations | Consolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	26,334	25,474
Carrying Amount of Liabilities	14,696	14,692
Credit card loan securitizations | Unconsolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	0	0
Carrying Amount of Liabilities	0	0
Auto loan securitizations
Variable Interest Entity [Line Items]
Maximum Exposure to Loss	0	0
Auto loan securitizations | Consolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	3,966	5,019
Carrying Amount of Liabilities	3,210	4,021
Auto loan securitizations | Unconsolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	0	0
Carrying Amount of Liabilities	0	0
Total securitization-related VIEs
Variable Interest Entity [Line Items]
Maximum Exposure to Loss	0	0
Total securitization-related VIEs | Consolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	30,300	30,493
Carrying Amount of Liabilities	17,906	18,713
Total securitization-related VIEs | Unconsolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	0	0
Carrying Amount of Liabilities	$ 0	$ 0