CONDENSED 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
Beginning Balance 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	134.4		134.4
Other comprehensive income (loss), net	(31.0)					(31.0)
Net transfers (to) from Parent	(65.5)		(65.5)
Ending Balance at Sep. 30, 2022	465.5	0.0	538.1	0.0	0.0	(72.6)
Beginning Balance at Jun. 30, 2022	468.9	0.0	530.0	0.0	0.0	(61.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	50.4		50.4
Other comprehensive income (loss), net	(11.5)					(11.5)
Net transfers (to) from Parent	(42.3)		(42.3)
Ending Balance at Sep. 30, 2022	465.5	0.0	538.1	0.0	0.0	(72.6)
Beginning Balance 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	136.5		84.1		52.4
Other comprehensive income (loss), net	(8.2)					(8.2)
Share-based awards	1.4			1.4
Net transfers (to) from Parent	(550.9)		(595.5)	44.6
Ending Balance at Sep. 30, 2023	34.4	0.0	0.0	46.0	52.4	(64.0)
Beginning Balance at Jun. 30, 2023	1.5	0.0	0.0	44.6	14.8	(57.9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	37.6				37.6
Other comprehensive income (loss), net	(6.1)					(6.1)
Share-based awards	1.4			1.4
Ending Balance at Sep. 30, 2023	$ 34.4	$ 0.0	$ 0.0	$ 46.0	$ 52.4	$ (64.0)