Finance Receivables, Net - Sale of Finance Receivables (Details) - USD ($) $ in Millions		3 Months Ended		12 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net carrying value (NCV) sold				$ 676	$ 682
Allowance included in NCV				17	18
Cash proceeds received				635	630
Beneficial interests received				$ 86	$ 101
Finance receivables sold and derecognized principal value		$ 196				$ 238
Finance receivables sold and derecognized sales value		$ 204				256
Finance Receivable Beneficial Interest Weighted Average Life		2 years
Impact from prior sales of finance receivables	[1]	$ (59)	$ (105)
Collections on beneficial interest		8	15
Estimated Decrease to Operating Cash Flows		(49)	(87)
Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collections on beneficial interest		10	$ 18
Other Current Assets [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beneficial Interest, Interest in Other Current Assets		32				38
Other Noncurrent Assets [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beneficial interest from sale of finance receivables		$ 23				$ 30

[1] Represents cash that would have been collected had we not sold finance receivables.