Finance Receivables, Net, Sale of Finance Receivables (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				12 Months Ended
	Mar. 31, 2015		Mar. 31, 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	450						549
Finance receivables sold and derecognized sales value	487						596
Beneficial Interest, Interest in Other Current Assets	66						77
Beneficial interest from sale of finance receivables	56						64
Finance Receivable Beneficial Interest Weighted Average Life	2 years
Collections on beneficial interest	15		21
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	(105)	[1]	(149)	[1]
Collections on beneficial interest	18		26
Estimated Decrease to Operating Cash Flows	$ (87)		$ (123)

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