Postretirement Benefit Plans - Rollforward of Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Change in plan assets
Plan assets as of January 1	$ 0.4	$ 0.5
Employer contributions	9.5	11.0
Benefits and expenses paid	(9.1)	(11.1)
Settlement	(0.4)	0.0
Plan assets as of December 31	0.4	0.4
Funded status at end of year	(150.2)	(149.4)
Pension Plan [Member]
Change in plan assets
Plan assets as of January 1	0.4
Plan assets as of December 31	0.4	0.4
Funded status at end of year	(84.0)	(78.7)
Pension Plan [Member] | International Plan [Member]
Change in plan assets
Plan assets as of January 1	0.4	0.5
Employer contributions	3.6	3.0
Benefits and expenses paid	(3.2)	(3.1)
Settlement	(0.4)	0.0
Plan assets as of December 31	0.4	0.4
Funded status at end of year	(72.8)	(67.5)
Pension Plan [Member] | United States
Change in plan assets
Plan assets as of January 1	0.0	0.0
Employer contributions	0.9	0.9
Benefits and expenses paid	(0.9)	(0.9)
Settlement	0.0	0.0
Plan assets as of December 31	0.0	0.0
Funded status at end of year	(11.2)	(11.2)
Other Postretirement Benefits Plan [Member]
Change in plan assets
Plan assets as of January 1	0.0	0.0
Employer contributions	5.0	7.1
Benefits and expenses paid	(5.0)	(7.1)
Settlement	0.0	0.0
Plan assets as of December 31	0.0	0.0
Funded status at end of year	$ (66.2)	$ (70.7)