Income Taxes (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Provision at the U.S. statutory rate of 35%	$ 70.6	$ 58.6	$ 67.1
Increase (reduction) in tax expense resulting from:
State income tax, net of federal income tax benefit	5.9	2.9	3.2
Other permanent items	(3.1)	(3.5)	(2.3)
Research tax credit	0	(0.3)	(0.5)
Change in unrecognized tax benefits	(5.1)	(0.6)	(0.2)
Change in valuation allowance	2.3	(0.7)	(1.8)
Foreign taxes at rates other than 35% and miscellaneous other	(3.9)	(0.6)	(0.7)
Total income tax provision	$ 66.7	$ 55.8	$ 64.8