Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Income Taxes (Textuals) [Abstract]
Tax Expense	$ 19	$ 48
Income before income taxes	50	56
Income Tax Reconciliation, Change in Enacted Tax Rate	12
Income Tax Reconciliation, Tax Contingencies		3
Unrecognized tax benefits, if recognized, would have a favorable impact on our tax expense			82
Tax expense, that would have a favorable impact of Unrecognized tax benefits			70
Accrued Interest			20
Unsettled unrecognized tax benefits that would require cash			$ 24