Finance Receivables and Loans, Net - Schedule of Financing Receivable Gross Charge-Offs (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year, writeoff			$ 65		$ 160
Year two, originated, fiscal year before current fiscal year, writeoff			405		779
Year three, originated, two years before current fiscal year, writeoff			574		943
Year four, originated, three years before current fiscal year, writeoff			518		511
Year five, originated, four years before current fiscal year, writeoff			254		137
More than five years before current fiscal year, writeoff			124		154
Revolving loans			65		248
Revolving loans converted to term			4		16
Total	$ 662	$ 744	2,009	$ 2,178	2,948
Write-downs from transfers to held-for-sale				5
Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year, writeoff			65		160
Year two, originated, fiscal year before current fiscal year, writeoff			405		779
Year three, originated, two years before current fiscal year, writeoff			574		943
Year four, originated, three years before current fiscal year, writeoff			518		511
Year five, originated, four years before current fiscal year, writeoff			253		137
More than five years before current fiscal year, writeoff			124		153
Revolving loans			64		246
Revolving loans converted to term			4		16
Total			2,007		2,945
Consumer | Automotive
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year, writeoff			65		160
Year two, originated, fiscal year before current fiscal year, writeoff			405		779
Year three, originated, two years before current fiscal year, writeoff			574		943
Year four, originated, three years before current fiscal year, writeoff			517		510
Year five, originated, four years before current fiscal year, writeoff			252		137
More than five years before current fiscal year, writeoff			124		152
Revolving loans			0		0
Revolving loans converted to term			0		0
Total	662	683	1,937	1,976	2,681
Write-downs from transfers to held-for-sale				5	5
Consumer | Consumer mortgage finance receivables
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year, writeoff			0		0
Year two, originated, fiscal year before current fiscal year, writeoff			0		0
Year three, originated, two years before current fiscal year, writeoff			0		0
Year four, originated, three years before current fiscal year, writeoff			1		1
Year five, originated, four years before current fiscal year, writeoff			1		0
More than five years before current fiscal year, writeoff			0		1
Revolving loans			0		0
Revolving loans converted to term			0		0
Total	0	0	2	1	2
Write-downs from transfers to held-for-sale				0
Consumer | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year, writeoff			0		0
Year two, originated, fiscal year before current fiscal year, writeoff			0		0
Year three, originated, two years before current fiscal year, writeoff			0		0
Year four, originated, three years before current fiscal year, writeoff			0		0
Year five, originated, four years before current fiscal year, writeoff			0		0
More than five years before current fiscal year, writeoff			0		0
Revolving loans			64		246
Revolving loans converted to term			4		16
Total		61	68	199	262
Write-downs from transfers to held-for-sale				0
Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year, writeoff			0		0
Year two, originated, fiscal year before current fiscal year, writeoff			0		0
Year three, originated, two years before current fiscal year, writeoff			0		0
Year four, originated, three years before current fiscal year, writeoff			0		0
Year five, originated, four years before current fiscal year, writeoff			1		0
More than five years before current fiscal year, writeoff			0		1
Revolving loans			1		2
Revolving loans converted to term			0		0
Total	$ 0	$ 0	2	2	3
Write-downs from transfers to held-for-sale				$ 0
Commercial | Automotive
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year, writeoff			0		0
Year two, originated, fiscal year before current fiscal year, writeoff			0		0
Year three, originated, two years before current fiscal year, writeoff			0		0
Year four, originated, three years before current fiscal year, writeoff			0		0
Year five, originated, four years before current fiscal year, writeoff			1		0
More than five years before current fiscal year, writeoff			0		1
Revolving loans			1		2
Revolving loans converted to term			0		0
Total			$ 2		$ 3