Restructuring - Restructuring Expense (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Restructuring Cost and Reserve [Line Items]
Cumulative amount of restructuring costs	$ 74.0		$ 71.0
Restructuring charges	3.0	$ 3.0
Restructuring Plan, 2018 | Severance and related expense
Restructuring Cost and Reserve [Line Items]
Cumulative amount of restructuring costs	27.6		25.4
Restructuring charges	2.2	2.2
Restructuring Plan, 2018 | Other
Restructuring Cost and Reserve [Line Items]
Cumulative amount of restructuring costs	45.7		45.6
Restructuring charges	0.1	0.1
Restructuring Plan, Other
Restructuring Cost and Reserve [Line Items]
Cumulative amount of restructuring costs	0.7
Restructuring Plan, Other | Other
Restructuring Cost and Reserve [Line Items]
Cumulative amount of restructuring costs	0.7		$ 0.0
Restructuring charges	$ 0.7	$ 0.7