Other Postretirement Benefit Plans - Change in Benefit Obligation, Plan Assets, Funded Status, and Balance Sheet Items (Details) - USD ($) $ in Millions	3 Months Ended					12 Months Ended
	Dec. 31, 2022	Jun. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Change in benefit obligation:
Actuarial gains	$ (12.3)	$ 11.6	$ (8.0)	$ 3.9	$ 3.5
Postretirement Plan
Change in benefit obligation:
Benefit obligation at beginning of year						$ 51.1	$ 57.6
Service cost						0.2	0.2	$ 0.2
Interest cost						1.4	1.5	2.1
Plan amendments						(0.6)	0.0
Actuarial gains						(13.1)	(4.1)
International plan exchange rate change						(0.1)	0.0
Benefits paid						(3.4)	(4.1)
Benefit obligation at end of year	$ 35.5		$ 51.1			$ 35.5	$ 51.1	$ 57.6