Restricted Cash (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash	$ 1,941	$ 2,071
Revolving Credit Facilities [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash	345	326
Securitization Notes Payable [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash	1,531	1,395
Other [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash	$ 65	$ 350