Finance Receivables, Net, Sale of Finance Receivables (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended		12 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014
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
Net fees and expenses						5	5
Finance receivables sold and derecognized principal value		$ 376		$ 376				$ 549
Finance receivables sold and derecognized sales value		404		404				596
Beneficial Interest, Interest in Other Current Assets		56		56				77
Beneficial interest from sale of finance receivables		46		$ 46				$ 64
Finance Receivable Beneficial Interest Weighted Average Life				2 years
Collections on beneficial interest		12	$ 21	$ 27	$ 42
Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Pre-tax gain on sales						$ 40	$ 44
Impact from prior sales of finance receivables	[1]	(89)	(137)	(194)	(286)
Collections on beneficial interest		15	25	33	51
Estimated Decrease to Operating Cash Flows		$ (74)	$ (112)	$ (161)	$ (235)

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