Intangible Assets (Schedule of Intangible Assets) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Jun. 30, 2014
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 826.8	$ 791.1
Accumulated Amortization	(113.3)	(104.3)
Total Net	713.5	686.8
Intangible Assets, Gross (Excluding Goodwill)	848.8	814.0
Intangible Assets, Net	735.5	709.7
Customer relationships [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	825.0	789.2
Accumulated Amortization	(113.2)	(104.2)
Total Net	711.8	685.0
Trade names [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	0.1	0.1
Total Net	0.1	0.1
Underlying rights [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	1.7	1.8
Accumulated Amortization	(0.1)	(0.1)
Total Net	1.6	1.7
Certifications [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount, Indefinite-lived Intangibles	3.5	3.5
Easement indefinite [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount, Indefinite-lived Intangibles	$ 18.5	$ 19.4