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	84.0		84.0
Other comprehensive loss, net of tax	(19.5)					(19.5)
Net transfers (to) from Parent	(23.2)		(23.2)
Ending Balance at Jun. 30, 2022	468.9	0.0	530.0	0.0	0.0	(61.1)
Beginning Balance at Mar. 31, 2022	463.9	0.0	505.2	0.0	0.0	(41.3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	49.2		49.2
Other comprehensive loss, net of tax	(19.8)					(19.8)
Net transfers (to) from Parent	(24.4)		(24.4)
Ending Balance at Jun. 30, 2022	468.9	0.0	530.0	0.0	0.0	(61.1)
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	98.9		84.1		14.8
Other comprehensive loss, net of tax	(2.1)					(2.1)
Net transfers (to) from Parent	(550.9)		(595.5)	44.6
Ending Balance at Jun. 30, 2023	1.5	0.0	0.0	44.6	14.8	(57.9)
Beginning Balance at Mar. 31, 2023	472.8	0.0	527.7	0.0	0.0	(54.9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	46.2		31.4		14.8
Other comprehensive loss, net of tax	(3.0)					(3.0)
Net transfers (to) from Parent	(514.5)		(559.1)	44.6
Ending Balance at Jun. 30, 2023	$ 1.5	$ 0.0	$ 0.0	$ 44.6	$ 14.8	$ (57.9)