Condensed Consolidated Statements of Comprehensive Income Parenthetical - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Net loss arising from remeasurement during the period, tax	$ 0.0	$ 0.0	$ 0.6	$ 0.0
Amortization of prior service benefits, tax	(1.3)	(1.4)	(4.1)	(4.2)
Amortization of net actuarial loss, tax	2.3	2.1	8.5	6.3
Reclassification adjustment for curtailment loss included in net income, tax	$ 0.0	$ 0.0	$ 0.1	$ 0.0