Restructuring (Narrative) (Details) $ in Millions	3 Months Ended					6 Months Ended
	Jun. 30, 2021 USD ($)	Sep. 30, 2020 employee	Jun. 30, 2020 USD ($)	Mar. 31, 2020 employee	Mar. 31, 2018 employee	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring (gains) charges, net	$ (0.2)		$ 23.2			$ (13.3)	$ 22.0
2020 Repositioning Actions
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected number of positions eliminated | employee		1,200
Restructuring and related cost, number of positions eliminated, period percent		11.00%
Restructuring (gains) charges, net	0.0		24.2			(0.5)	24.2
2019 Repositioning Actions
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected number of positions eliminated | employee				180
Restructuring and related cost, number of positions eliminated, period percent				1.00%
Restructuring (gains) charges, net						0.1	0.0
2017 Repositioning Actions
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected number of positions eliminated | employee					300
Restructuring and related cost, number of positions eliminated, period percent					3.00%
Restructuring (gains) charges, net	$ (0.2)		$ (1.0)			$ (12.9)	$ (2.5)