CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Millions	Total	Common Stock	Net Parent Investment	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Balance at beginning of period at Dec. 31, 2020	$ 445.3	$ 0.0	$ 475.6	$ 0.0	$ 0.0	$ (30.3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	170.1		170.1
Other comprehensive loss, net of tax	(11.3)					(11.3)
Share-based awards	0.0
Net transfers (to) from Parent	(176.5)		(176.5)
Balance at end of period at Dec. 31, 2021	427.6	0.0	469.2	0.0	0.0	(41.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	170.4		170.4
Other comprehensive loss, net of tax	(14.2)					(14.2)
Share-based awards	0.0
Net transfers (to) from Parent	(128.2)		(128.2)
Balance at end of period at Dec. 31, 2022	455.6	0.0	511.4	0.0	0.0	(55.8)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	171.3		84.1		87.2
Other comprehensive loss, net of tax	(0.4)					(0.4)
Share-based awards	4.3			4.3
Net transfers (to) from Parent	(550.1)		(595.5)	45.4
Balance at end of period at Dec. 31, 2023	$ 80.7	$ 0.0	$ 0.0	$ 49.7	$ 87.2	$ (56.2)