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, 2017	Jun. 30, 2016
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	$ 1,362.7	$ 1,319.6
Fair value of plan assets	987.4	884.9
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	255.1	246.0
Fair value of plan assets	$ 117.0	$ 115.6