Finance Receivables and Loans, Net (Allowance for Credit Losses on Financing Receivables) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Jun. 30, 2022	Dec. 31, 2021
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance, beginning balance	$ 3,781	$ 3,450	$ 3,711	$ 3,267
Charge-offs	(677)	(447)	(1,907)	(1,079)
Recoveries	221	171	643	517
Net charge-offs	(456)	(276)	(1,264)	(562)
Provision for credit losses	512	438	1,390	907
Other	0	(1)	0	(1)
Allowance, ending balance	3,837	3,611	3,837	3,611
Unfunded Loan Commitment
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Provision for credit losses	(4)		(9)	2
Consumer
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Charge-offs			(1,845)
Consumer | Automotive
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance, beginning balance	3,064	2,885	3,020	2,769
Charge-offs	(602)	(381)	(1,634)	(934)
Recoveries	209	164	613	496
Net charge-offs	(393)	(217)	(1,021)	(438)
Provision for credit losses	433	326	1,106	663
Other	0	(1)	(1)	(1)
Allowance, ending balance	3,104	2,993	3,104	2,993
Consumer | Consumer mortgage
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance, beginning balance	23	26	27	27
Charge-offs	0	(1)	(3)	(3)
Recoveries	2	2	7	10
Net charge-offs	2	1	4	7
Provision for credit losses	(4)	(1)	(9)	(7)
Other	1	1	0	0
Allowance, ending balance	22	27	22	27
Consumer | Consumer other
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance, beginning balance	476	303	426	221
Charge-offs	(74)	(33)	(208)	(84)
Recoveries	6	4	18	8
Net charge-offs	(68)	(29)	(190)	(76)
Provision for credit losses	68	99	239	228
Other	(2)	(1)	(1)	(1)
Allowance, ending balance	474	372	474	372
Fair value, option, carrying amount, financing receivable, no allowance		6		6	$ 3	$ 7	$ 7
Commercial
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance, beginning balance	218	236	238	250
Charge-offs	(1)	(32)	(62)	(58)
Recoveries	4	1	5	3
Net charge-offs	3	(31)	(57)	(55)
Provision for credit losses	15	14	54	23
Other	1	0	2	1
Allowance, ending balance	$ 237	$ 219	237	$ 219
Commercial | Automotive
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Charge-offs			(5)
Commercial | Consumer other
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Charge-offs			$ (57)