Related Party Transactions - Narrative (Details) - USD ($)	1 Months Ended		12 Months Ended
	Mar. 31, 2023	Feb. 28, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Related Party Transaction [Line Items]
Revenue			$ 14,224,000,000	$ 12,766,000,000	$ 13,419,000,000
Related party tax payments			$ 72,000,000	690,000,000	824,000,000
Line of Credit
Related Party Transaction [Line Items]
Debt instrument term (in years)			5 years
Line of Credit | General Motors | Five Year Revolving Credit Facility
Related Party Transaction [Line Items]
Maximum borrowing capacity		$ 11,200,000,000
Debt instrument term (in years)		5 years	5 years
Current borrowing capacity	$ 10,000,000,000		$ 10,000,000,000
Line of Credit | General Motors | 364-Day Revolving Credit Facility
Related Party Transaction [Line Items]
Debt instrument term (in years)	364 days
Revolving credit facilities | Line of Credit | Cruise, LLC
Related Party Transaction [Line Items]
Cruise receivables			353,000,000	113,000,000
Maximum borrowing capacity			3,400,000,000
Revolving credit facilities | Line of Credit | General Motors
Related Party Transaction [Line Items]
Maximum borrowing capacity			$ 14,100,000,000
Revolving credit facilities | Line of Credit | General Motors | Three Year Revolving Credit Facility Expiring April 2024
Related Party Transaction [Line Items]
Maximum borrowing capacity		$ 4,300,000,000
Debt instrument term (in years)		3 years	3 years
Current borrowing capacity	$ 4,100,000,000		$ 4,100,000,000
Revolving credit facilities | Line of Credit | General Motors | 364-Day Revolving Credit Facility
Related Party Transaction [Line Items]
Maximum borrowing capacity			$ 2,000,000,000
Debt instrument term (in years)			364 days
Junior Subordinated Revolving Credit Facility | General Motors
Related Party Transaction [Line Items]
Line of credit facilities - GM related party facility			$ 1,000,000,000
GM
Related Party Transaction [Line Items]
Revenue			$ 3,500,000,000	$ 2,400,000,000	$ 3,300,000,000