Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 23.8	$ 16.6
Defined benefit pension and other postretirement employee benefits:
Amortization of actuarial (gain) loss included in net periodic cost, net of immaterial tax and $0.4	(0.1)	1.1
Other comprehensive income (loss), net of tax	(0.1)	1.1
Comprehensive income	$ 23.8	$ 17.7