Income Taxes (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Net unrecognized tax benefit	$ 57,600,000		$ 57,600,000		$ 43,900,000
Income tax interest and penalties accrued	0		0
Deferred tax assets	$ 151,000,000		$ 151,000,000
Effective tax rate	15.50%	13.90%	11.10%	8.60%
U.S. federal statutory rate			35.00%