Restructuring and Severance - Summary of activity in the restructuring and severance liability (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Restructuring Cost and Reserve [Line Items]
Beginning Balance	$ 4.0	$ 10.2		$ 10.2
Charges	(0.3)	0.2	$ 0.0	(0.1)	$ 0.0
Reversals	(0.3)
Utilizations	(3.5)	(6.4)
Ending Balance	0.2	4.0		0.2
Corporate [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	0.4	0.5		0.5
Charges		0.0
Reversals	0.0
Utilizations	(0.3)	(0.1)
Ending Balance	0.1	0.4		0.1
Network [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	3.6	9.7		9.7
Charges		0.2
Reversals	(0.3)
Utilizations	(3.2)	(6.3)
Ending Balance	$ 0.1	$ 3.6		$ 0.1