STATEMENTS OF CONSOLIDATED COMPREHENSIVE (LOSS) INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (29.6)	$ (18.5)	$ 28.8
Other comprehensive income (loss), net of tax - Note 11:
Defined benefit plans	24.2	(1.6)	13.4
Available for sale securities			(0.3)
Cash flow hedges	(17.3)	16.6	6.7
Foreign currency translation			0.1
Other comprehensive income (loss), net of tax	6.9	15.0	19.9
Comprehensive (loss) income	$ (22.7)	$ (3.5)	$ 48.7