Variable Interest Entities and Securitizations - Carrying Amount of Consolidated and Unconsolidated VIEs (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Variable Interest Entity [Line Items]
Maximum Exposure to Loss	$ 5,070	$ 5,157
Carrying Amount of Assets	434,195	432,381
Carrying Amount of Liabilities	377,850	371,352
Consolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	24,851	26,458
Carrying Amount of Liabilities	14,317	15,256
Unconsolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	5,070	5,157
Carrying Amount of Liabilities	1,439	1,454
Affordable housing entities
Variable Interest Entity [Line Items]
Maximum Exposure to Loss	4,703	4,774
VIE, nonconsolidated, carrying amount of assets included in certain investment structures	2,200	2,200
VIE, nonconsolidated, carrying amount of liabilities included in certain investment structures	551	568
Affordable housing entities | Consolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	297	263
Carrying Amount of Liabilities	53	27
Affordable housing entities | Unconsolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	4,703	4,774
Carrying Amount of Liabilities	1,439	1,454
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	2,198	2,074
Carrying Amount of Liabilities	26	26
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	367	383
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	367	383
Carrying Amount of Liabilities	0	0
Total other VIEs
Variable Interest Entity [Line Items]
Maximum Exposure to Loss	5,070	5,157
Total other VIEs | Consolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	2,495	2,337
Carrying Amount of Liabilities	79	53
Total other VIEs | Unconsolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	5,070	5,157
Carrying Amount of Liabilities	1,439	1,454
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	20,127	21,569
Carrying Amount of Liabilities	12,348	13,016
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	2,229	2,552
Carrying Amount of Liabilities	1,890	2,187
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	22,356	24,121
Carrying Amount of Liabilities	14,238	15,203
Total securitization-related VIEs | Unconsolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	0	0
Carrying Amount of Liabilities	$ 0	$ 0