Finance Receivables and Loans, Net - Schedule of Allowance for Credit Losses on Financing Receivables (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance, beginning balance	$ 3,714	$ 3,587	$ 3,587
Charge-offs	(745)	(758)	(2,948)
Recoveries	238	219
Net charge-offs	(507)	(539)
Write-downs from transfers to held-for-sale		(5)
Provision for credit losses	191	507
Other	0
Allowance, ending balance	3,398	3,550	3,714
Consumer
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Charge-offs	(744)		(2,945)
Consumer | Automotive
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance, beginning balance	3,170	3,083	3,083
Charge-offs	(676)	(688)	(2,681)
Recoveries	231	211
Net charge-offs	(445)	(477)
Write-downs from transfers to held-for-sale		(5)	(5)
Provision for credit losses	418	449
Other	1
Allowance, ending balance	3,144	3,050	3,170
Consumer | Consumer mortgage finance receivables
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance, beginning balance	19	21	21
Charge-offs	0	(1)	(2)
Recoveries	1	1
Net charge-offs	1	0
Write-downs from transfers to held-for-sale		0
Provision for credit losses	0	0
Other	(2)
Allowance, ending balance	18	21	19
Consumer | Consumer other
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance, beginning balance	319	293	293
Charge-offs	(68)	(68)	(262)
Recoveries	5	6
Net charge-offs	(63)	(62)
Write-downs from transfers to held-for-sale		0
Provision for credit losses	(257)	60
Other	1
Allowance, ending balance	0	291	319
Commercial
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance, beginning balance	206	190	190
Charge-offs	(1)	(1)	(3)
Recoveries	1	1
Net charge-offs	0	0
Write-downs from transfers to held-for-sale		0
Provision for credit losses	30	(2)
Other	0
Allowance, ending balance	236	$ 188	206
Commercial | Automotive
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Charge-offs	$ (1)		$ (3)