Securitization Notes Payable Securitization Notes Payable (Narrative) (Details) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2012	Dec. 31, 2011
Debt Instrument [Line Items]
Amortization of Debt Discount (Premium)	$ (27,458,000)	$ (31,648,000)	$ (67,671,000)
Purchase Price Premium, Unamortized		11,200,000	42,400,000
Unamortized Debt Issuance - Securitization Notes Payable		26,100,000	16,300,000
Securitization Notes Payable [Member]
Debt Instrument [Line Items]
Amortization of Debt Discount (Premium)	25,700,000	31,300,000	64,700,000
Fiscal 2013 [Member]
Debt Instrument [Line Items]
Expected Principal Payments on Trusts		3,406,200,000
Fiscal 2014 [Member]
Debt Instrument [Line Items]
Expected Principal Payments on Trusts		2,324,000,000
Fiscal 2015 [Member]
Debt Instrument [Line Items]
Expected Principal Payments on Trusts		1,771,600,000
Fiscal 2016 [Member]
Debt Instrument [Line Items]
Expected Principal Payments on Trusts		1,073,200,000
Fiscal 2017 [Member]
Debt Instrument [Line Items]
Expected Principal Payments on Trusts		$ 437,800,000