Accumulated Other Comprehensive Income (Loss) Reclassification Adjustments (Details) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended					7 Months Ended	9 Months Ended
	Aug. 11, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Aug. 11, 2023	Sep. 30, 2022
Interest Expense	$ 26.4	$ 42.9			$ 50.7			$ 178.0	$ 148.4
Net pension settlements	0.0	0.0			14.3			0.0	14.3
Total reclassifications for the period	1.1	0.0	$ 0.8	$ 1.3	12.9	$ (0.1)	$ (0.1)	3.2	13.1
Reclassification out of Accumulated Other Comprehensive Income [Member]
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	$ 1.1	0.0			$ (1.4)			3.2	(0.6)
Accumulated Net Gain (Loss) from Interest Rate Hedge [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Interest Expense		$ 0.0						$ 0.0	$ 0.6