Long-Term Debt (Summary of Long-Term Debt) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Jun. 30, 2016
Debt Instrument [Line Items]
Debt obligations	$ 4,167.4	$ 4,167.4
Unamortized discount	(17.1)	(19.0)
Unamortized debt issuance costs	(49.9)	(53.8)
Carrying value of debt	4,091.3	4,085.3
6.00% Senior Notes due 2023 [Member]
Debt Instrument [Line Items]
Unamortized premium	$ 5.9	6.3
Interest rate	6.00%
6.375% Senior Notes due 2025 [Member]
Debt Instrument [Line Items]
Unamortized discount	$ (15.0)	(15.6)
Interest rate	6.375%
Term Loan Facility due 2021 [Member]
Debt Instrument [Line Items]
Debt obligations	$ 1,837.4	1,837.4
Carrying value of debt	1,820.3	1,818.4
Unsecured Debt [Member] \| 6.00% Senior Notes due 2023 [Member]
Debt Instrument [Line Items]
Debt obligations	1,430.0	1,430.0
Unsecured Debt [Member] \| 6.375% Senior Notes due 2025 [Member]
Debt Instrument [Line Items]
Debt obligations	$ 900.0	$ 900.0

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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Contractual interest rate for funds borrowed, under the debt agreement.

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Amount, after accumulated amortization, of debt discount.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28541-108399

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

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Amount, after accumulated amortization, of debt premium.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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-Name Accounting Standards Codification
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
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The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

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