UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS)
Net income (loss)	$ (100.6)	$ 99.8	$ (181.3)	$ 96.1
Other comprehensive income:
Defined benefit pension and retiree health benefit plans	0.1	0.1	0.2	0.2
Total other comprehensive income	0.1	0.1	0.2	0.2
Comprehensive income (loss) attributable to stockholders' equity	$ (100.5)	$ 99.9	$ (181.1)	$ 96.3