Income Taxes Changes in Unrecognized Tax Benefits (Details) (Federal and State [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Federal and State [Member]
Changes in Unrecognized Tax Benefits [Line Items]
Unrecognized Tax Benefits	$ 137	$ 133	$ 132
Unrecognized Tax Benefits, Increases Resulting from Prior Period Tax Positions	1	12
Unrecognized Tax Benefits, Decreases Resulting from Prior Period Tax Positions	(2)	(12)
Unrecognized Tax Benefits, Increases Resulting from Current Period Tax Positions	45	8
Unrecognized Tax Benefits, Decreases Resulting from Settlements with Taxing Authorities	34	1
Unrecognized Tax Benefits, Reductions Resulting from Lapse of Applicable Statute of Limitations	$ 6	$ 6