Pension and Other Postretirement Benefits - Schedule of Fair Values of Pension Plan by Assets Category (Details) - USD ($) $ in Millions	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2020
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	$ 759.4	999.4	$ 923.4
Pension Benefits | Short-term investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	25.5	21.6
Pension Benefits | Domestic and international equities
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		156.3
Pension Benefits | Commingled trust funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	732.8	404.9
Pension Benefits | Limited partnerships
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		52.4
Pension Benefits | Government agency bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		176.2
Pension Benefits | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		183.1
Pension Benefits | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		2.4
Pension Benefits | Mortgage/asset backed securities and other
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	1.1	2.5
Pension Benefits | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	25.5	166.3
Pension Benefits | Level 1 | Short-term investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	25.5	0.0
Pension Benefits | Level 1 | Domestic and international equities
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		156.3
Pension Benefits | Level 1 | Commingled trust funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	0.0	0.0
Pension Benefits | Level 1 | Limited partnerships
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0.0
Pension Benefits | Level 1 | Government agency bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0.0
Pension Benefits | Level 1 | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		7.6
Pension Benefits | Level 1 | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		2.4
Pension Benefits | Level 1 | Mortgage/asset backed securities and other
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	0.0	0.0
Pension Benefits | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	1.1	375.8
Pension Benefits | Level 2 | Short-term investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	0.0	21.6
Pension Benefits | Level 2 | Domestic and international equities
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0.0
Pension Benefits | Level 2 | Commingled trust funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	0.0	0.0
Pension Benefits | Level 2 | Limited partnerships
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0.0
Pension Benefits | Level 2 | Government agency bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		176.2
Pension Benefits | Level 2 | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		175.5
Pension Benefits | Level 2 | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0.0
Pension Benefits | Level 2 | Mortgage/asset backed securities and other
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	1.1	2.5
Pension Benefits | Net Asset Value
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	732.8	457.3
Pension Benefits | Net Asset Value | Short-term investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	0.0	0.0
Pension Benefits | Net Asset Value | Domestic and international equities
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0.0
Pension Benefits | Net Asset Value | Commingled trust funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	732.8	404.9
Pension Benefits | Net Asset Value | Limited partnerships
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		52.4
Pension Benefits | Net Asset Value | Government agency bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0.0
Pension Benefits | Net Asset Value | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0.0
Pension Benefits | Net Asset Value | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets		0.0
Pension Benefits | Net Asset Value | Mortgage/asset backed securities and other
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	$ 0.0	$ 0.0