CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Other comprehensive income:
Tax benefit, Pension and postretirement liability adjustments	$ (3.9)	$ (1.0)	$ (0.3)
Tax benefit, Change in fair value of cash flow hedges	(0.1)	(0.1)	(0.4)
Tax benefit, Reclassification adjustment for hedge gains and losses included in net income (loss)	$ (0.2)	$ (0.1)	$ (0.2)