Repurchase Agreements And Other Debt (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012 years	Dec. 31, 2011
Debt Instrument [Line Items]
Weighted Average Life of Other Debt	5.2
Secured Debt, Dollar Rolls	$ 12,900,000,000
Risk of repurchase agreement to stockholders equity	4.00%
Other Long-term Debt	937,000,000	54,000,000
Debt Instrument, Face Amount	$ 908,000,000	$ 54,000,000
Debt Instrument, Description of Variable Rate Basis, LIBOR	LIBOR
Spread Over LIBOR	43	25