Pension and Other Postretirement Benefits - Schedule of Components of the Net Periodic Pension (Income) Expense (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2024	Dec. 31, 2023
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1.9	$ 2.0	$ 3.8	$ 4.2
Interest cost	9.7	11.8	19.4	23.6
Expected return on plan assets	(7.5)	(10.1)	(15.0)	(20.2)
Amortization of net loss (gain)	1.9	2.2	3.8	4.4
Amortization of prior service cost (credits)	0.5	0.5	1.0	1.0
Net pension expense (income)	6.5	6.4	13.0	13.0
Other Postretirement Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.4	0.4	0.8	0.7
Interest cost	2.5	2.5	5.0	5.0
Expected return on plan assets	(2.1)	(1.8)	(4.2)	(3.7)
Amortization of net loss (gain)	(1.4)	(0.6)	(2.8)	(1.2)
Amortization of prior service cost (credits)	0.3	(1.0)	0.6	(2.0)
Net pension expense (income)	$ (0.3)	$ (0.5)	$ (0.6)	$ (1.2)