Finance Receivables, Net - Sale of Finance Receivables (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended		12 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 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		$ 163		$ 163				$ 238
Finance receivables sold and derecognized sales value		154		$ 154				256
Finance Receivable Beneficial Interest Weighted Average Life				2 years
Impact from prior sales of finance receivables	[1]	(51)	$ (89)	$ (110)	$ (194)
Collections on beneficial interest		7	12	15	27
Estimated decrease to operating cash flows		(43)	(74)	(92)	(161)
Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collections on beneficial interest		8	$ 15	18	$ 33
Other Current Assets [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beneficial Interest, Interest in Other Current Assets		26		26				38
Other Noncurrent Assets [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beneficial interest from sale of finance receivables		$ 17		$ 17				$ 30

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