Pension and Other Postretirement Benefits - Schedule of Components of the Net Periodic Pension (Income) Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Pension settlement charge	$ 51.9	$ 0.0	$ 51.9	$ 0.0
Net pension expense (income)	0.5
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	2.1	2.0	6.2	5.9
Interest cost	10.4	11.5	34.0	34.5
Expected return on plan assets	(8.3)	(11.2)	(28.5)	(33.6)
Amortization of net loss (gain)	1.9	2.4	6.2	7.2
Amortization of prior service cost (credits)	0.5	0.5	1.6	1.5
Pension settlement charge	51.9	0.0	51.9	0.0
Net pension expense (income)	58.5	5.2	71.4	15.5
Other Postretirement Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.3	0.5	1.1	1.5
Interest cost	2.6	2.4	7.6	7.2
Expected return on plan assets	(1.8)	(1.7)	(5.5)	(5.1)
Amortization of net loss (gain)	(0.6)	(0.4)	(1.9)	(1.2)
Amortization of prior service cost (credits)	(1.0)	(1.0)	(2.9)	(3.0)
Pension settlement charge	0.0	0.0	0.0	0.0
Net pension expense (income)	$ (0.5)	$ (0.2)	$ (1.6)	$ (0.6)