Finance Receivables and Loans, Net (Allowance for Credit Losses on Financing Receivables) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance, beginning balance	$ 3,751	$ 3,301	$ 3,711	$ 3,267
Charge-offs	(629)	(331)	(1,230)	(632)
Recoveries	230	178	422	346
Net charge-offs	(399)	(153)	(808)	(286)
Provision for credit losses	429	302	878	469
Other	0	0	0	0
Allowance, ending balance	3,781	3,450	3,781	3,450
Unfunded Loan Commitment
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Provision for credit losses	(2)	2	(5)	2
Consumer
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Charge-offs			(1,169)
Consumer | Automotive
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance, beginning balance	3,022	2,763	3,020	2,769
Charge-offs	(496)	(277)	(1,032)	(553)
Recoveries	219	169	404	332
Net charge-offs	(277)	(108)	(628)	(221)
Provision for credit losses	320	230	673	337
Other	(1)	0	(1)	0
Allowance, ending balance	3,064	2,885	3,064	2,885
Consumer | Consumer mortgage
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance, beginning balance	23	26	27	27
Charge-offs	(2)	(1)	(3)	(2)
Recoveries	3	5	5	8
Net charge-offs	1	4	2	6
Provision for credit losses	(2)	(3)	(6)	(6)
Other	1	(1)	0	(1)
Allowance, ending balance	23	26	23	26
Consumer | Consumer other
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance, beginning balance	455	258	426	221
Charge-offs	(70)	(27)	(134)	(51)
Recoveries	7	3	12	4
Net charge-offs	(63)	(24)	(122)	(47)
Provision for credit losses	84	70	172	129
Other	0	(1)	0	0
Allowance, ending balance	476	303	476	303
Fair value, option, carrying amount, financing receivable, no allowance		7		7	$ 2	$ 3	$ 7	$ 7
Commercial
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance, beginning balance	251	254	238	250
Charge-offs	(61)	(26)	(61)	(26)
Recoveries	1	1	1	2
Net charge-offs	(60)	(25)	(60)	(24)
Provision for credit losses	27	5	39	9
Other	0	2	1	1
Allowance, ending balance	$ 218	$ 236	218	$ 236
Commercial | Automotive
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Charge-offs			(4)
Commercial | Consumer other
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Charge-offs			$ (57)