Equity in Net Assets of Non-consolidated Affiliates - Summarized Financial Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Undistributed earnings of foreign subsidiaries	$ 5	$ 21
SAIC-GMAC [Member]
Schedule of Equity Method Investments [Line Items]
Cash dividends received	129	0
Undistributed earnings of foreign subsidiaries	142	121
Summarized Balance Sheet Data(a):
Finance receivables, net	10,408	9,617
Total assets	11,089	9,802
Debt	6,681	5,789
Total liabilities	9,330	7,973
Summarized Operating Data(a):
Finance charge income	940	971
Provision for loan losses	18	45
Interest expense	257	338
Income before income taxes	570	463
Net income	$ 428	$ 347
Ownership percentage	35.00%