Restructuring (Narrative) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2021 USD ($)	Jun. 30, 2020 employee	Mar. 31, 2020 USD ($)	Dec. 31, 2019 employee	Dec. 31, 2017 employee
Restructuring Cost and Reserve [Line Items]
Restructuring gain, net	$ (13.1)		$ (1.2)
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 gain, net	(0.5)		0.0
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 gain, 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 gain, net	$ (12.7)		$ (1.5)