CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income before allocation to noncontrolling interests	$ 181.1	$ 133.6	$ 335.5
Other comprehensive income (loss), net of tax
Currency translation adjustment	70.4	11.5	(41.6)
Changes in pension and postretirement plan assets and benefit obligation, net of tax	(53.6)	(47.7)	(26.2)
Other comprehensive income (loss), net of tax	16.8	(36.2)	(67.8)
Comprehensive income before allocation to noncontrolling interests	197.9	97.4	267.7
Less: Noncontrolling interests in comprehensive income	(0.5)	(0.1)	(0.3)
Comprehensive income attributable to common shareholders	$ 198.4	$ 97.5	$ 268.0