Finance Receivables - Allowance for Loan Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Provision for loan losses	$ 669	$ 624	$ 604
Automobile Loan [Member] | Retail Finance Receivables [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	735	655	497
Provision for loan losses	666	612	613
Charge-offs	(1,171)	(996)	(914)
Recoveries	559	486	470
Foreign currency translation	4	(22)	(11)
Balance at end of period	$ 793	$ 735	$ 655