Condensed Consolidated Statements of Comprehensive Income (Loss) Parenthetical (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Net gain arising from remeasurement during the period, tax		$ 13.1		$ 17.3
Amortization of prior service benefits, tax	(1.4)	(1.3)	(4.2)	(3.7)
Amortization of net loss included in net income, tax	2.1	2.4	6.3	7.5
Reclassification adjustment for curtailment gain included in net income, tax				$ (0.2)