Pension and Other Postretirement Benefits - Schedule of Amounts Recognized in the Consolidated Balance Sheets (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Pension Benefits
Amounts recognized in accumulated other comprehensive loss:
Net actuarial loss	$ 362.1	$ 451.3
Prior service cost (credit)	16.2	18.3
Total	378.3	469.6
Other changes in plan assets and benefit obligations recognized in other comprehensive loss consist of:
Net actuarial gain	(75.0)	(59.1)
Amortization of net loss	(13.5)	(37.8)
Prior service cost	0.0	18.6
Amortization of prior service (cost) benefit	(2.1)	(1.8)
Total, before tax effect	(90.6)	(80.1)
Additional information:
Accumulated benefit obligation for all pension plans	1,257.8	1,362.8
Other Benefits
Amounts recognized in accumulated other comprehensive loss:
Net actuarial loss	32.9	52.2
Prior service cost (credit)	(23.1)	(28.2)
Total	9.8	24.0
Other changes in plan assets and benefit obligations recognized in other comprehensive loss consist of:
Net actuarial gain	(16.3)	(5.7)
Amortization of net loss	(2.9)	(3.2)
Prior service cost	0.0	10.7
Amortization of prior service (cost) benefit	5.2	6.5
Total, before tax effect	$ (14.0)	$ 8.3