Receivables Receivables - Contractual Maturities (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012
Receivables, Contractual Obligations
2013	$ 199
2014	65
2015	78
2016	129
2017	168
Thereafter	32,300
Total	32,939
First Lien
Receivables, Contractual Obligations
2013	101
2014	45
2015	58
2016	91
2017	125
Thereafter	28,881
Total	29,301
Second Mortgage [Member]
Receivables, Contractual Obligations
2013	98
2014	20
2015	20
2016	38
2017	43
Thereafter	3,419
Total	$ 3,638