Employee Retirement Plans (Details 3) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Amounts Recognized in Other Comprehensive Income (Loss)
Actuarial gain (loss)	$ (47.3)	$ 11.9	$ 18.7
Amortization of actuarial loss	1.7	1.9	4.2
Amortization of prior service cost	0.1	0.1	0.1
Other		(0.2)
Curtailments			33.5
Settlements		0.2
Total before income taxes	(45.5)	13.9	56.5
Income tax expense (benefit)	(16.9)	5.2	20.9
Net amount recognized in other comprehensive income (loss)	$ (28.6)	$ 8.7	$ 35.6