Restructuring (Narrative) (Details) $ in Millions	3 Months Ended			12 Months Ended
	Dec. 31, 2022 employee	Jun. 30, 2020 officeFacility warehouseFacility employee	Dec. 31, 2017 employee	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring charges (gains), net				$ 0.5	$ 6.2	$ (3.7)
2022 Restructuring
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated | employee	140
Number of positions eliminated, percent of global workforce	4.00%
Restructuring charges (gains), net				0.5	6.2	0.0
Additional expected restructuring costs				0.0
2020 Restructuring
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated | employee		600
Number of positions eliminated, percent of global workforce		15.00%
Restructuring charges (gains), net				0.0	0.0	(3.6)
2020 Restructuring | Office Facilities
Restructuring Cost and Reserve [Line Items]
Number of exited lease properties | officeFacility		2
2020 Restructuring | Warehouse Facility
Restructuring Cost and Reserve [Line Items]
Number of exited lease properties | warehouseFacility		1
2017 Restructuring
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated | employee			70
Number of positions eliminated, percent of global workforce			2.00%
Restructuring charges (gains), net				$ 0.0	$ 0.0	$ (0.2)