Securitizations and Variable Interest Entities (Schedule of Variable Interest Entities) (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022
Variable Interest Entity [Line Items]
Carrying value of total assets	$ 195,704	$ 191,826	$ 188,640
Carrying value of total liabilities	182,879	178,967
Assets sold to nonconsolidated VIEs	966	330
Maximum exposure to loss in nonconsolidated VIEs	3,826	3,097
Non-recourse debt	20,096	17,762
Equity securities	725	681
On-balance sheet variable interest entities
Variable Interest Entity [Line Items]
Carrying value of total assets	9,826	9,856
Carrying value of total liabilities	3,125	2,441
Non-recourse debt	3,118	2,436
On-balance sheet variable interest entities | Consumer | Automotive
Variable Interest Entity [Line Items]
Carrying value of total assets	19,532	20,415
Carrying value of total liabilities	3,230	2,553
Assets sold to nonconsolidated VIEs	0	0
Maximum exposure to loss in nonconsolidated VIEs	0	0
Assets held-in-trust	9,700	10,600
On-balance sheet variable interest entities | Consumer | Automotive | Nonrecourse
Variable Interest Entity [Line Items]
Non-recourse debt	105	113
Off-balance sheet variable interest entities
Variable Interest Entity [Line Items]
Carrying value of total assets	21,810	22,614
Carrying value of total liabilities	4,052	3,426
Off-balance sheet variable interest entities | Consumer | Automotive
Variable Interest Entity [Line Items]
Carrying value of total assets	0	0
Carrying value of total liabilities	0	0
Assets sold to nonconsolidated VIEs	835	227
Maximum exposure to loss in nonconsolidated VIEs	835	227
Off-balance sheet variable interest entities | Consumer | Other
Variable Interest Entity [Line Items]
Carrying value of total assets	0	0
Carrying value of total liabilities	0	0
Assets sold to nonconsolidated VIEs	131	103
Maximum exposure to loss in nonconsolidated VIEs	131	103
Off-balance sheet variable interest entities | Commercial | Other
Variable Interest Entity [Line Items]
Carrying value of total assets	2,278	2,199
Carrying value of total liabilities	822	873
Assets sold to nonconsolidated VIEs	0	0
Maximum exposure to loss in nonconsolidated VIEs	2,860	2,767
Equity securities	$ 44	$ 38