Intangible Assets (Schedule of Identifiable Acquisition Related Intangible Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Jun. 30, 2015
Schedule Of Intangible Assets Net Excluding Goodwill [Line Items]
Gross Carrying Amount	$ 1,127.4	$ 1,082.2
Accumulated Amortization	(211.2)	(155.3)
Total Net	916.2	926.9
Intangible Assets, Gross (Excluding Goodwill)	1,147.3	1,103.6
Intangible Assets, Net	936.1	948.3
Certifications [Member]
Schedule Of Intangible Assets Net Excluding Goodwill [Line Items]
Gross Carrying Amount, Indefinite-lived Intangibles	3.5	3.5
Easement indefinite [Member]
Schedule Of Intangible Assets Net Excluding Goodwill [Line Items]
Gross Carrying Amount, Indefinite-lived Intangibles	16.4
Customer relationships [Member]
Schedule Of Intangible Assets Net Excluding Goodwill [Line Items]
Gross Carrying Amount	1,125.5	1,080.3
Accumulated Amortization	(210.7)	(155.0)
Total Net	914.8	925.3
Trade names [Member]
Schedule Of Intangible Assets Net Excluding Goodwill [Line Items]
Gross Carrying Amount	0.2	0.2
Accumulated Amortization	(0.2)	(0.1)
Total Net		0.1
Underlying rights [Member]
Schedule Of Intangible Assets Net Excluding Goodwill [Line Items]
Gross Carrying Amount	1.7	1.7
Accumulated Amortization	(0.3)	(0.2)
Total Net	$ 1.4	1.5
Gross Carrying Amount, Indefinite-lived Intangibles		$ 17.9