Pension and Other Postretirement Benefits - Schedule of Amounts Recognized in the Consolidated Balance Sheets (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Pension Benefits
Amounts recognized in accumulated other comprehensive loss:
Net actuarial loss	$ 487.2	$ 445.7
Prior service cost (credit)	12.0	14.1
Total	499.2	459.8
Other changes in plan assets and benefit obligations recognized in other comprehensive loss consist of:
Net actuarial loss	56.9	94.1
Amortization of net loss	(15.5)	(10.4)
Amortization of prior service (cost) benefit	(2.1)	(2.1)
Total, before tax effect	39.3	81.6
Additional information:
Accumulated benefit obligation for all pension plans	1,335.2	1,331.6
Other Benefits
Amounts recognized in accumulated other comprehensive loss:
Net actuarial loss	53.3	42.3
Prior service cost (credit)	(14.0)	(17.9)
Total	39.3	24.4
Other changes in plan assets and benefit obligations recognized in other comprehensive loss consist of:
Net actuarial loss	13.5	10.9
Amortization of net loss	(2.5)	(1.6)
Amortization of prior service (cost) benefit	3.9	5.2
Total, before tax effect	$ 14.9	$ 14.5