Supplemental Information for the Consolidated Statements of Cash Flows - Noncash Activity (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Supplemental Cash Flow Elements [Abstract]
Subvention receivable from GM	$ 360	$ 508	$ 469
Commercial loan funding payable to GM	$ 100	$ 55	$ 105