Benefit Plans and Other Postretirement Benefits, Level 3 plan assets (Details) - Pension Benefits - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure
Fair value of plan assets at the beginning of the year	$ 581.0	$ 514.1
Foreign currency translation	5.0	2.5
Fair value of plan assets at end of year	632.3	581.0
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure
Fair value of plan assets at the beginning of the year	47.7	45.3
Unrealized gains (losses), net	1.1	4.0
Purchases, sales and settlements, net	(1.0)	(1.2)
Foreign currency translation	3.0	(0.4)
Fair value of plan assets at end of year	$ 50.8	$ 47.7