Finance Receivables and Loans, Net (Allowance for Credit Losses on Financing Receivables) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Loan and Lease Losses [Roll Forward]
Allowance, beginning balance	$ 3,267	$ 3,283
Charge-offs	(301)	(308)
Recoveries	168	190
Net charge-offs	(133)	(118)
Provision for credit losses	167	(13)
Other	0	0
Allowance, ending balance	3,301	3,152
Consumer | Automotive
Financing Receivable, Allowance for Loan and Lease Losses [Roll Forward]
Allowance, beginning balance	2,769	2,902
Charge-offs	(276)	(284)
Recoveries	163	187
Net charge-offs	(113)	(97)
Provision for credit losses	107	4
Other	0	0
Allowance, ending balance	2,763	2,809
Consumer | Mortgage/Real Estate
Financing Receivable, Allowance for Loan and Lease Losses [Roll Forward]
Allowance, beginning balance	27	33
Charge-offs	(1)	(2)
Recoveries	3	3
Net charge-offs	2	1
Provision for credit losses	(3)	(7)
Other	0	(1)
Allowance, ending balance	26	26
Consumer | Other
Financing Receivable, Allowance for Loan and Lease Losses [Roll Forward]
Allowance, beginning balance	221	73
Charge-offs	(24)	(8)
Recoveries	1	0
Net charge-offs	(23)	(8)
Provision for credit losses	59	3
Other	1	1
Allowance, ending balance	258	69
Finance receivables, fair value	7	8	$ 7	$ 8
Commercial
Financing Receivable, Allowance for Loan and Lease Losses [Roll Forward]
Allowance, beginning balance	250	275
Charge-offs	0	(14)
Recoveries	1	0
Net charge-offs	1	(14)
Provision for credit losses	4	(13)
Other	(1)	0
Allowance, ending balance	$ 254	$ 248