Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Cumulative foreign currency translation	$ (33.4)	$ 17.1
Unrecognized pension costs (net of tax benefit of $41.0 in 2014 and $23.6 in 2013)	(82.1)	(51.0)
Unrealized gain (loss) on cash flow hedges (net of tax expense of $1.0 in 2014 and $1.0 in 2013)	2.6	2.6
Total accumulated other comprehensive income (loss)	(112.9)	(31.3)
Unrecognized pension costs net of tax benefit	41.0	23.6
Unrealized gain (loss) on cash flow hedges net of tax expense	1.0	1.0
Foreign currency translation adjustment
Foreign currency translation adjustment, pre-tax amount	(51.5)	(16.5)
Foreign currency translation adjustment, tax (expense) benefit)	0	0
Foreign currency translation adjustments, net-of-tax amount	(51.5)	(16.5)	1.5
Cashflow hedges
Unrealized gains (losses) arising during period, pre-tax amount	0	0.8
Unrealized gains (losses) arising during period, tax (expense) benefit)	0	(0.3)
Unrealized gains (losses) arising during period, net-of-tax amount	0	0.5	(0.2)
Reclassification of net (gains) losses to net income, pre-tax amount	0	0
Reclassification of net (gains) losses to net income, tax (expense) benefit)	0	0
Reclassification of net (gains) losses to net income, net-of-tax amount	0	0
Pension plans
Net actuarial gains (losses) and prior service costs arising during the period, pre-tax amount	(53.7)	68.6
Net actuarial gains (losses) and prior service costs arising during the period, tax (expense) benefit)	19.1	(26.7)
Net actuarial gains (losses) and prior service costs arising during the period, net-of-tax amount	(34.6)	41.9
Amortization of net actuarial (gains) losses and prior service costs, pre-tax amount	5.2	(12.4)
Amortization of net actuarial (gains) losses and prior service costs, tax (expense) benefit)	(1.7)	4.8
Amortization of net actuarial (gains) losses and prior service costs, net-of-tax amount	3.5	(7.6)
Total other comprehensive income (loss), pre-tax amount	(100.0)	40.5
Total other comprehensive income (loss)	17.4	(22.2)
Total other comprehensive income (loss), net of tax	$ (82.6)	$ 18.3