Asset-Backed Financing (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011 SPEs [Member]	Dec. 31, 2010 SPEs [Member]	Dec. 31, 2011 SPEs Facility [Member]	Dec. 31, 2010 SPEs Facility [Member]	Sep. 09, 2011 SPEs Facility [Member]
Asset-Backed Financing [Line Items]
Assets transferred to special purpose entities	$ 1,210,000,000	$ 670,800,000	$ 3,080,000,000
Total aggregate commitment								600,000,000
Expiration date of conduit facility						September 7, 2012
Financial services interest expense	$ 229,492,000	$ 272,484,000	$ 283,634,000	$ 60,200,000	$ 106,300,000	$ 1,500,000	$ 9,300,000
Weighted average interest rate of asset-backed securitization transactions				1.96%	3.11%
Weighted average interest rate of conduit facility	0.00%	0.00%