Debt Short Term and Long Term Debt (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Short Term and Long Term Debt [Line Items]
Secured debt	$ 22,073	$ 9,378
Unsecured debt	6,973	1,500
Revolving Credit Facility [Member]
Short Term and Long Term Debt [Line Items]
Secured debt	9,000
Unsecured debt	2,973
Securitization Notes Payable [Member]
Short Term and Long Term Debt [Line Items]
Secured debt	13,073
Senior Notes [Member]
Short Term and Long Term Debt [Line Items]
Unsecured debt	4,000
North America Segment [Member]
Short Term and Long Term Debt [Line Items]
Secured debt	12,479	9,378
Unsecured debt	4,000	1,500
North America Segment [Member] | Revolving Credit Facility [Member]
Short Term and Long Term Debt [Line Items]
Secured debt	1,678	354
Unsecured debt	0	0
North America Segment [Member] | Securitization Notes Payable [Member]
Short Term and Long Term Debt [Line Items]
Secured debt	10,801	9,024
North America Segment [Member] | Senior Notes [Member]
Short Term and Long Term Debt [Line Items]
Unsecured debt	4,000	1,500
International Segment [Member]
Short Term and Long Term Debt [Line Items]
Secured debt	9,594
Unsecured debt	2,973
International Segment [Member] | Revolving Credit Facility [Member]
Short Term and Long Term Debt [Line Items]
Secured debt	7,322
Unsecured debt	2,973
International Segment [Member] | Securitization Notes Payable [Member]
Short Term and Long Term Debt [Line Items]
Secured debt	2,272
International Segment [Member] | Senior Notes [Member]
Short Term and Long Term Debt [Line Items]
Unsecured debt	$ 0