Equity in Net Assets of Non-consolidated Affiliates (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 30, 2022	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Noncontrolling Interest [Line Items]
Finance charge income		$ 1,158	$ 1,035	$ 3,230	$ 3,087
Income before income taxes		911	1,093	3,301	3,856
Net income		44	53	148	157
Remaining dividend payment				1,144	1,920
Joint Ventures
Noncontrolling Interest [Line Items]
Finance charge income		391	406	1,266	1,254
Income before income taxes		168	205	564	599
Net income		126	$ 154	424	$ 450
Undistributed earnings		$ 889		$ 889		$ 740
SAIC-GMAC
Noncontrolling Interest [Line Items]
Cash dividends received	$ 26