Pension and Other Postretirement Benefits - Schedule of Projected Benefit Obligations in Excess of Plan Assets and Accumulated Benefit Obligations in Excess of Plan Assets (Details) - USD ($) $ in Millions	Jun. 30, 2021	Jun. 30, 2020
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	$ 1,217.6	$ 1,335.1
Fair value of plan assets	999.4	923.3
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	249.3	264.2
Fair value of plan assets	$ 136.3	$ 112.8