Pension, Post-Retirement and Post-Employment Plans - Fair Value of Plan Assets by Asset Category (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure
Total	$ 228.8	$ 211.9
Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure
Total	106.1	202.0
Assets using net asset value (or NAV) as a practical expedient
Defined Benefit Plan Disclosure
Total	122.7	9.9
Derivatives | Level 2
Defined Benefit Plan Disclosure
Total	14.0	9.9
Foreign equities | Level 1
Defined Benefit Plan Disclosure
Total	5.8	5.4
Foreign bonds | Level 2
Defined Benefit Plan Disclosure
Total	1.6	1.3
Mutual funds holding U.S. Treasury securities | Level 1
Defined Benefit Plan Disclosure
Total	30.8	20.3
Mutual funds holding fixed income securities | Level 1
Defined Benefit Plan Disclosure
Total	23.5	121.9
U.S. Treasury bonds | Level 2
Defined Benefit Plan Disclosure
Total	22.6	36.4
Cash and cash equivalents | Level 1
Defined Benefit Plan Disclosure
Total	$ 7.8	$ 6.8