Equity in Net Assets of Nonconsolidated Affiliates - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Schedule of Equity Method Investments [Line Items]
Undistributed earnings of foreign subsidiaries	$ 713	$ 454
Other-than-temporary impairment charges	320	0	$ 0
Equity in net assets of nonconsolidated affiliates (Note 6)	1,206	1,670
Gmac Saic
Schedule of Equity Method Investments [Line Items]
Dividends declared	491	273	342
Cash dividends received	172	96	$ 120
Equity in net assets of nonconsolidated affiliates (Note 6)	$ 1,500
Gmac Saic | Measurement Input, Cost to Sell [Member]
Schedule of Equity Method Investments [Line Items]
Investment measurement input	0.130
Gmac Saic | Measurement Input, Long-Term Revenue Growth Rate [Member]
Schedule of Equity Method Investments [Line Items]
Investment measurement input	0.035
Non-consolidated affiliates
Schedule of Equity Method Investments [Line Items]
Undistributed earnings of foreign subsidiaries	$ 729	$ 837