Securitizations and Variable Interest Entities (Schedule of Variable Interest Entities) (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021
Variable Interest Entity [Line Items]
Carrying value of total assets	$ 185,703	$ 182,114	$ 180,470
Carrying value of total liabilities	171,719	165,064
Non-recourse debt	16,984	17,029
Other assets	8,882	8,057
On-balance sheet variable interest entities
Variable Interest Entity [Line Items]
Carrying value of total assets	8,007	7,509
Carrying value of total liabilities	1,502	1,339
Non-recourse debt	1,500	1,337
Other assets	546	563
On-balance sheet variable interest entities | Consumer | Automotive loan
Variable Interest Entity [Line Items]
Carrying value of total assets	18,613	18,158
Carrying value of total liabilities	1,622	1,162
Assets sold to nonconsolidated VIEs	0	0
Maximum exposure to loss in nonconsolidated VIEs	0	0
Assets held-in-trust	10,600	11,000
On-balance sheet variable interest entities | Consumer | Automotive loan | Nonrecourse
Variable Interest Entity [Line Items]
Non-recourse debt	120	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	20,668	20,290
Carrying value of total liabilities	2,462	2,188
Assets sold to nonconsolidated VIEs	42	0
Maximum exposure to loss in nonconsolidated VIEs	2,619	2,416
Off-balance sheet variable interest entities | Consumer | Automotive loan
Variable Interest Entity [Line Items]
Carrying value of total assets	0
Carrying value of total liabilities	0
Assets sold to nonconsolidated VIEs	2
Maximum exposure to loss in nonconsolidated VIEs	2
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	40
Maximum exposure to loss in nonconsolidated VIEs	40
Off-balance sheet variable interest entities | Commercial | Other
Variable Interest Entity [Line Items]
Carrying value of total assets	2,055	1,814
Carrying value of total liabilities	840	726
Assets sold to nonconsolidated VIEs	0	0
Maximum exposure to loss in nonconsolidated VIEs	2,577	2,416
Other assets	$ 1	$ 8