Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Income Taxes (Textual) [Abstract]
Income tax provision	$ 28	$ 5	$ 75	$ 72
Effective tax rate	27.80%	6.30%	25.20%	24.00%
Likelihood of uncertain tax positions			greater than 50%
Tax benefit			50.00%
Unrecognized tax benefits	$ 7		$ 7
Interest accrued for unrecognized tax benefits			less than $1 million
Period for unrecognized tax benefit significant change			12 months