Securitizations and Variable Interest Entities (Schedule of Variable Interest Entities) (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Variable Interest Entity [Line Items]
Carrying value of total assets	$ 184,297	$ 182,114	$ 181,879
Carrying value of total liabilities	168,884	165,064
Other assets	8,957	8,057
On-balance sheet variable interest entities
Variable Interest Entity [Line Items]
Carrying value of total assets	8,188	7,509
Carrying value of total liabilities	799	1,339
Other assets	633	563
On-balance sheet variable interest entities | Consumer | Automotive loan
Variable Interest Entity [Line Items]
Carrying value of total assets	19,016	18,158
Carrying value of total liabilities	917	1,162
Assets sold to nonconsolidated VIEs	0	0
Maximum exposure to loss in nonconsolidated VIEs	0	0
Assets held-in-trust	10,800	11,000
Non-recourse debt	118	124
On-balance sheet variable interest entities | Consumer | Other
Variable Interest Entity [Line Items]
Carrying value of total assets		318
Carrying value of total liabilities		300
Assets sold to nonconsolidated VIEs		0
Maximum exposure to loss in nonconsolidated VIEs		0
Off-balance sheet variable interest entities
Variable Interest Entity [Line Items]
Carrying value of total assets	20,885	20,290
Carrying value of total liabilities	1,633	2,188
Assets sold to nonconsolidated VIEs	13	0
Maximum exposure to loss in nonconsolidated VIEs	2,436	2,416
Off-balance sheet variable interest entities | Consumer | Other
Variable Interest Entity [Line Items]
Carrying value of total assets	0
Carrying value of total liabilities	0
Assets sold to nonconsolidated VIEs	13
Maximum exposure to loss in nonconsolidated VIEs	13
Off-balance sheet variable interest entities | Commercial | Other
Variable Interest Entity [Line Items]
Carrying value of total assets	1,869	1,814
Carrying value of total liabilities	716	726
Assets sold to nonconsolidated VIEs	0	0
Maximum exposure to loss in nonconsolidated VIEs	2,423	2,416
Other assets	$ 1	$ 8