Other Comprehensive (Loss) Income - Components of Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pre-tax
Other comprehensive income (loss), pre-tax	$ (50.0)	$ 115.2	$ 1.8
Tax
Total other comprehensive income (loss), tax	(6.1)	(1.4)	0.1
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]
Total other comprehensive income (loss), net of tax	(56.1)	113.8	1.9
Cumulative translation adjustment
Pre-tax
Other comprehensive income (loss) before reclassifications, before tax			0.1
Other comprehensive income (loss), pre-tax	(75.6)	107.8
Tax
Total other comprehensive income (loss), tax	0.0	0.0	0.0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]
Total other comprehensive income (loss), net of tax	(75.6)	107.8
Net gain (loss) arising during the year
Pre-tax
Other comprehensive income (loss) before reclassifications, before tax	12.0	(1.5)	(7.4)
Tax
Other comprehensive income (loss) before reclassifications, tax	(2.9)	0.1	2.4
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]
Other comprehensive income (loss) before reclassifications, net of tax	9.1	(1.4)	(5.0)
Amortization and settlement loss, net of curtailment gain
Pre-tax
Reclassifications from AOCI before tax	10.3	2.9	2.8
Tax
Reclassification from AOCI, tax	(2.4)	(0.1)	(0.9)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]
Reclassification from AOCI, net of tax	7.9	2.8	1.9
Pension and other postretirement adjustments
Pre-tax
Other comprehensive income (loss), pre-tax	22.3	1.4	(4.6)
Tax
Total other comprehensive income (loss), tax	(5.3)	0.0	1.5
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]
Total other comprehensive income (loss), net of tax	17.0	1.4	(3.1)
Reclassification adjustments for derivatives
Pre-tax
Other comprehensive income (loss), pre-tax	3.3	6.0	6.3
Tax
Total other comprehensive income (loss), tax	(0.8)	(1.4)	(1.4)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]
Total other comprehensive income (loss), net of tax	$ 2.5	$ 4.6	$ 4.9