Debt Short Term and Long Term Debt (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Short Term and Long Term Debt [Line Items]
Secured Debt	$ 18,447	$ 9,378
Unsecured Debt	5,228	1,500
Revolving Credit Facility [Member]
Short Term and Long Term Debt [Line Items]
Secured Debt	6,090
Unsecured Debt	1,228
Securitization Notes Payable [Member]
Short Term and Long Term Debt [Line Items]
Secured Debt	12,357
Senior Notes [Member]
Short Term and Long Term Debt [Line Items]
Unsecured Debt	4,000
North America [Member]
Short Term and Long Term Debt [Line Items]
Secured Debt	11,807	9,378
Unsecured Debt	4,000	1,500
North America [Member] | Revolving Credit Facility [Member]
Short Term and Long Term Debt [Line Items]
Secured Debt	1,337	354
North America [Member] | Securitization Notes Payable [Member]
Short Term and Long Term Debt [Line Items]
Secured Debt	10,470	9,024
North America [Member] | Senior Notes [Member]
Short Term and Long Term Debt [Line Items]
Unsecured Debt	4,000	1,500
International [Member]
Short Term and Long Term Debt [Line Items]
Secured Debt	6,640
Unsecured Debt	1,228
International [Member] | Revolving Credit Facility [Member]
Short Term and Long Term Debt [Line Items]
Secured Debt	4,753
Unsecured Debt	1,228
International [Member] | Securitization Notes Payable [Member]
Short Term and Long Term Debt [Line Items]
Secured Debt	1,887
International [Member] | Senior Notes [Member]
Short Term and Long Term Debt [Line Items]
Unsecured Debt