Benefit Plans, Defined Benefit Pension Plan Assets Measured at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Fair value of plan assets [Abstract]
Fair value of plan assets	$ 358.2	$ 340.0
U.S. Plans [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	271.6	261.5	$ 227.1
International Plans [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	86.6	78.5	$ 69.6
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	280.7	270.5
Significant Other Observable Inputs (Level 2) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	69.2	61.6
Significant Unobservable Inputs (Level 3) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	8.3	7.9
Equity Securities [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	200.0	187.5
US Equities [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	182.0	169.7
US Equities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	182.0	169.7
US Equities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	0.0	0.0
US Equities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	0.0	0.0
Non-US Equities [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	18.0	17.8
Non-US Equities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	18.0	17.8
Non-US Equities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	0.0	0.0
Non-US Equities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	0.0	0.0
Fixed Income Securities [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	99.7	98.8
Corporate Debt Instruments [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	99.7	98.8
Corporate Debt Instruments [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	80.4	82.6
Corporate Debt Instruments [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	19.3	16.2
Corporate Debt Instruments [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	0.0	0.0
Real Estate [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	1.0	0.9
Real Estate [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	0.0	0.0
Real Estate [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	0.0	0.0
Real Estate [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	1.0	0.9
Other [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	57.5	52.8
Other [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	0.3	0.4
Other [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	49.9	45.4
Other [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	$ 7.3	$ 7.0