CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Other Comprehensive Income (Loss), Tax [Abstract]
Amortization of deferred holding gains on derivatives designated as cash flow hedges included in net earnings, tax benefit	$ 0.6	$ 0.5	$ 0.5
Net loss, tax benefit	1.1	24.9	20.2
Net gain on remeasurement of postretirement benefit plan liability, tax expense	0	7.4	0
Amortization, tax expense	$ 0.8	$ 5.1	$ 3.1