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Long-Term Debt (Narrative) (Details) - USD ($) $ in Millions							3 Months Ended			12 Months Ended
	Apr. 10, 2017	Jan. 19, 2017	Jul. 22, 2016	Apr. 14, 2016	Jan. 15, 2016	May 06, 2015	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015	Jan. 27, 2017	Mar. 09, 2015	Jan. 23, 2015	Aug. 13, 2012
Debt Instrument [Line Items]
Payments of Debt Extinguishment Costs											$ 20.3	$ 62.6
Cumulative proceeds from issuance of private placement										$ 3,865.8	929.3	1,787.3
Redemption of debt										2,408.8	535.0	1,288.5
Loss on extinguishment of debt							$ 13.7	$ 4.5	$ 33.8	18.2	33.8	94.3
Debt obligations							5,608.7		4,167.4	5,608.7	4,167.4
Debt issuance costs							112.9			112.9
Accumulated amortization							45.1		35.8	45.1	35.8
Debt Issuance Costs, Net							18.2			18.2
Interest expense associated with the amortization of debt issuance costs										$ 9.3	10.0	13.9
Revolver [Member]
Debt Instrument [Line Items]
Percentage of excess cash flows committed to debt payments										35.00%
Outstanding letters of credit							0.0			$ 0.0
Remaining borrowing capacity							$ 442.2			$ 442.2
Secured debt ratio							5.25			5.25
Unsecured credit letter agreement
Debt Instrument [Line Items]
Outstanding letters of credit							$ 7.8			$ 7.8
Interest Rate Swap [Member]
Debt Instrument [Line Items]
Derivative, notional amount																$ 750.0
Derivative, fixed interest rate																1.67%
Derivative, floor rate																1.25%
Change in fair value of interest rate swap										3.0	1.1	(2.1)
Interest Rate Swap [Member] \| Other long-term liabilities
Debt Instrument [Line Items]
Fair value of interest rate swaps							0.0		3.0	0.0	3.0
Secured Debt [Member] \| Revolver [Member]
Debt Instrument [Line Items]
Line of credit facility maximum borrowing capacity							50.0			$ 50.0
Line of credit facility maturity date										Apr. 17, 2020
Unused commitment, percentage										0.25%
Term Loan Facility
Debt Instrument [Line Items]
Interest rate decrease (basis point)			75.00%
Discount on debt							$ 16.0		$ 19.0	$ 16.0	$ 19.0
Weighted average interest rate (including margins)							3.40%		3.90%	3.40%	3.90%
Outstanding letters of credit							$ 1,928.7			$ 1,928.7
Debt instrument, face amount		$ 1,850.0
Repriced percentage		99.75%
Incremental Term Loan [Member]
Debt Instrument [Line Items]
Line of credit facility increase to borrowing capacity					$ 400.0
Priced percent of additional line of credit					99.00%
Discount on debt					$ 4.8
Unamortized Debt Issuance Costs
Debt Instrument [Line Items]
Loss on extinguishment of debt										$ 10.4	$ 11.4	$ 23.2
2023 Unsecured Notes [Member]
Debt Instrument [Line Items]
Secured debt ratio							4.50			4.50
Total indebtedness ratio							6.00			6.00
Minimum \| Secured Debt [Member] \| Revolver [Member]
Debt Instrument [Line Items]
Unused commitment, percentage										0.25%
Minimum \| Term Loan Facility \| Revolver [Member]
Debt Instrument [Line Items]
Effective Interest rates (in percent)							3.80%		3.40%	3.80%	3.40%
Maximum \| Secured Debt [Member] \| Revolver [Member]
Debt Instrument [Line Items]
Unused commitment, percentage										0.375%
Tranche One [Member] \| Term Loan Facility
Debt Instrument [Line Items]
Debt instrument, face amount		$ 500.0
Tranche Two [Member] \| Term Loan Facility
Debt Instrument [Line Items]
Debt instrument, face amount		1,350.0
6.00% Senior Notes due 2023 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount														$ 730.0	$ 700.0
Cumulative proceeds from issuance of private placement										$ 1,437.3
6.00% Senior Notes due 2023 [Member] \| Unsecured Notes
Debt Instrument [Line Items]
Debt instrument, redemption price, percentage										100.00%
Interest rate of debt redeemed							6.00%		6.00%	6.00%	6.00%
Debt obligations							$ 1,430.0		$ 1,430.0	$ 1,430.0	$ 1,430.0
6.375% Senior Notes due 2025 [Member]
Debt Instrument [Line Items]
Discount on debt				$ 15.9
Debt instrument, face amount				550.0
Redemption premium and accrued interest included in redemption amount				20.3
Loss on extinguishment of debt				2.1
Debt obligations				196.0
6.375% Senior Notes due 2025 [Member] \| Unsecured Notes
Debt Instrument [Line Items]
Discount on debt							$ 14.3		$ 15.6	$ 14.3	$ 15.6
Interest rate of debt redeemed							6.375%		6.375%	6.375%	6.375%
Debt obligations							$ 900.0		$ 900.0	$ 900.0	$ 900.0
5.75% Senior Unsecured Notes due 2027 [Member]
Debt Instrument [Line Items]
Outstanding letters of credit	$ 1,350.0
Debt instrument, face amount	$ 550.0												$ 800.0
Repriced percentage	104.00%
Redemption premium	$ 22.0
Interest rate of debt redeemed	5.75%												5.75%
5.75% Senior Unsecured Notes due 2027 [Member] \| Unsecured Notes
Debt Instrument [Line Items]
Interest rate of debt redeemed							5.75%		5.75%	5.75%	5.75%
Debt obligations							$ 1,350.0			$ 1,350.0
10.125% Senior Notes due 2020 [Member]
Debt Instrument [Line Items]
Redemption of debt				$ 325.6
Interest rate of debt redeemed				10.125%
$650 Million Term Loan [Member] \| Term Loan Facility \| Electric Lightwave
Debt Instrument [Line Items]
Debt instrument, face amount		650.0
Amendment and Restatement Agreement [Member] \| Secured Debt [Member] \| Revolver [Member]
Debt Instrument [Line Items]
Line of credit facility maximum borrowing capacity						$ 450.0
Amendment and Restatement Agreement [Member] \| Term Loan Facility
Debt Instrument [Line Items]
Payment towards principal						$ 5.1
Percentage of excess cash flows committed to debt payments						50.00%
Term Loan 2500 Million [Member] \| Term Loan Facility \| Electric Lightwave
Debt Instrument [Line Items]
Debt instrument, face amount		$ 2,500.0
Repriced percentage		99.75%
March Notes Offering [Member]
Debt Instrument [Line Items]
Debt instrument, face amount							$ 7.3			$ 7.3
Priced percent of new debt										1.00%
New 2025 Notes [Member] \| Term Loan Facility \| Electric Lightwave
Debt Instrument [Line Items]
Redemption of debt	$ 570.1
8.125% Senior First Priority Notes due 2020 [Member]
Debt Instrument [Line Items]
Priced percent of additional line of credit				97.76%
8.125% Senior First Priority Notes due 2020 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Redemption of debt										$ 675.0
Redemption premium										$ 38.8
8.125% Senior First Priority Notes due 2020 [Member] \| Secured Debt [Member] \| Second Note Redemption [Member]
Debt Instrument [Line Items]
Debt instrument, redemption price, percentage										105.75%
LIBOR \| Term Loan Facility
Debt Instrument [Line Items]
Spread on interest rate			2.75%
LIBOR \| Incremental Term Loan [Member]
Debt Instrument [Line Items]
Spread on interest rate					3.50%
LIBOR \| Minimum \| Secured Debt [Member] \| Revolver [Member]
Debt Instrument [Line Items]
Spread on interest rate										2.00%
LIBOR \| Minimum \| Term Loan Facility
Debt Instrument [Line Items]
Spread on interest rate			1.00%
LIBOR \| Minimum \| Incremental Term Loan [Member]
Debt Instrument [Line Items]
Spread on interest rate					1.00%
LIBOR \| Maximum \| Secured Debt [Member] \| Revolver [Member]
Debt Instrument [Line Items]
Spread on interest rate										3.00%
LIBOR \| Tranche One [Member] \| Term Loan Facility
Debt Instrument [Line Items]
Interest rate decrease (basis point)		75.00%
Spread on interest rate		2.00%
LIBOR \| Tranche One [Member] \| Minimum \| Term Loan Facility
Debt Instrument [Line Items]
Spread on interest rate		0.00%
LIBOR \| Tranche Two [Member] \| Term Loan Facility
Debt Instrument [Line Items]
Interest rate decrease (basis point)		25.00%
Spread on interest rate		2.50%
LIBOR \| Tranche Two [Member] \| Minimum \| Term Loan Facility
Debt Instrument [Line Items]
Spread on interest rate		1.00%
LIBOR \| $650 Million Term Loan [Member] \| Term Loan Facility \| Electric Lightwave
Debt Instrument [Line Items]
Spread on interest rate		2.50%
LIBOR \| $650 Million Term Loan [Member] \| Minimum \| Term Loan Facility \| Electric Lightwave
Debt Instrument [Line Items]
Spread on interest rate		1.00%
LIBOR \| Amendment and Restatement Agreement [Member] \| Term Loan Facility
Debt Instrument [Line Items]
Interest rate decrease (basis point)						25.00%
Spread on interest rate						2.75%
LIBOR \| Amendment and Restatement Agreement [Member] \| Minimum \| Term Loan Facility
Debt Instrument [Line Items]
Spread on interest rate						1.00%