Variable Interest Entities - Narrative (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Variable Interest Entity [Line Items]
Assets	$ 49,346,000,000		$ 47,724,000,000
Liabilities	42,143,000,000		40,332,000,000
Revenues	1,354,000,000	1,097,000,000
Net income	150,000,000	145,000,000
Transfers of Finance Receivables	2,000,000,000		2,500,000,000
Transfers of Finance Receivables Outstanding Balance	1,800,000,000		2,400,000,000
Germany [Member] | Subsidiaries [Member]
Variable Interest Entity [Line Items]
Assets	4,200,000,000		4,500,000,000
Liabilities	3,500,000,000		4,000,000,000
Revenues	41,000,000	58,000,000
Net income	$ 11,000,000	$ 10,000,000