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, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year, writeoff			$ 65		$ 239
Year two, originated, current fiscal year, writeoff			567		1,034
Year three, originated, current fiscal year, writeoff			719		680
Year four, originated, current fiscal year, writeoff			397		197
Year five, originated, current fiscal year, writeoff			108		221
More than five years before current fiscal year, writeoff			122		151
Revolving loans			188		188
Revolving loans converted to term			12		10
Total	$ 744	$ 677	2,178	$ 1,907	2,720
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		239
Year two, originated, current fiscal year, writeoff			567		1,034
Year three, originated, current fiscal year, writeoff			719		680
Year four, originated, current fiscal year, writeoff			397		197
Year five, originated, current fiscal year, writeoff			108		142
More than five years before current fiscal year, writeoff			121		123
Revolving loans			187		165
Revolving loans converted to term			12		10
Total			2,176		2,590
Consumer | Automotive
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year, writeoff			65		225
Year two, originated, current fiscal year, writeoff			567		952
Year three, originated, current fiscal year, writeoff			719		651
Year four, originated, current fiscal year, writeoff			396		194
Year five, originated, current fiscal year, writeoff			108		142
More than five years before current fiscal year, writeoff			121		120
Revolving loans			0		0
Revolving loans converted to term			0		0
Total	683	602	1,976	1,634	2,284
Write-downs from transfers to held-for-sale			5		41
Consumer | Consumer mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year, writeoff			0		0
Year two, originated, current fiscal year, writeoff			0		0
Year three, originated, current fiscal year, writeoff			0		0
Year four, originated, current fiscal year, writeoff			1		0
Year five, originated, current fiscal year, writeoff			0		0
More than five years before current fiscal year, writeoff			0		3
Revolving loans			0		0
Revolving loans converted to term			0		0
Total	0	0	1	3	3
Write-downs from transfers to held-for-sale			0
Consumer | Mortgage Finance
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year, writeoff			0		0
Year two, originated, current fiscal year, writeoff			0		0
Year three, originated, current fiscal year, writeoff			0		0
Year four, originated, current fiscal year, writeoff			1		0
Year five, originated, current fiscal year, writeoff			0		0
More than five years before current fiscal year, writeoff			0		1
Revolving loans			0		0
Revolving loans converted to term			0		0
Total			1		1
Consumer | Mortgage — Legacy
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year, writeoff					0
Year two, originated, current fiscal year, writeoff					0
Year three, originated, current fiscal year, writeoff					0
Year four, originated, current fiscal year, writeoff					0
Year five, originated, current fiscal year, writeoff					0
More than five years before current fiscal year, writeoff					2
Revolving loans					0
Revolving loans converted to term					0
Total					2
Consumer | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year, writeoff			0		14
Year two, originated, current fiscal year, writeoff			0		82
Year three, originated, current fiscal year, writeoff			0		29
Year four, originated, current fiscal year, writeoff			0		3
Year five, originated, current fiscal year, writeoff			0		0
More than five years before current fiscal year, writeoff			0		0
Revolving loans			187		165
Revolving loans converted to term			12		10
Total	61	74	199	208	303
Write-downs from transfers to held-for-sale			0		174
Consumer | Personal Lending
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year, writeoff					14
Year two, originated, current fiscal year, writeoff					82
Year three, originated, current fiscal year, writeoff					29
Year four, originated, current fiscal year, writeoff					3
Year five, originated, current fiscal year, writeoff					0
More than five years before current fiscal year, writeoff					0
Revolving loans					0
Revolving loans converted to term					0
Total					128
Consumer | Credit Card
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year, writeoff			0		0
Year two, originated, current fiscal year, writeoff			0		0
Year three, originated, current fiscal year, writeoff			0		0
Year four, originated, current fiscal year, writeoff			0		0
Year five, originated, current fiscal year, writeoff			0		0
More than five years before current fiscal year, writeoff			0		0
Revolving loans			187		165
Revolving loans converted to term			12		10
Total			199		175
Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year, writeoff			0		0
Year two, originated, current fiscal year, writeoff			0		0
Year three, originated, current fiscal year, writeoff			0		0
Year four, originated, current fiscal year, writeoff			0		0
Year five, originated, current fiscal year, writeoff			0		79
More than five years before current fiscal year, writeoff			1		28
Revolving loans			1		23
Revolving loans converted to term			0		0
Total	$ 0	$ 1	2	$ 62	130
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, current fiscal year, writeoff			0		0
Year three, originated, current fiscal year, writeoff			0		0
Year four, originated, current fiscal year, writeoff			0		0
Year five, originated, current fiscal year, writeoff			0		0
More than five years before current fiscal year, writeoff			1		5
Revolving loans			1		19
Revolving loans converted to term			0		0
Total			$ 2		24
Commercial | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year, writeoff					0
Year two, originated, current fiscal year, writeoff					0
Year three, originated, current fiscal year, writeoff					0
Year four, originated, current fiscal year, writeoff					0
Year five, originated, current fiscal year, writeoff					79
More than five years before current fiscal year, writeoff					23
Revolving loans					4
Revolving loans converted to term					0
Total					$ 106