Credit Facility (Details)	1 Months Ended	12 Months Ended
	Feb. 28, 2017 USD ($)	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Jun. 30, 2017 USD ($)
Line of Credit Facility [Line Items]
Interest coverage ratio, less than		3.50
Debt issuance amortization	$ 33,700,000	$ 40,100,000	$ 46,800,000
Description of variable rate basis		the highest of JPMorgan Chase Bank, N.A.'s prime rate, the federal funds rate plus a margin equal to 0.50% and the adjusted LIBOR rate for a 1-month interest period plus a margin equal to 1.00%
Interest expense		$ 199,000,000	146,300,000	$ 104,000,000
Foreign Line of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity		125,000,000
Standby Letters of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity		25,000,000
Line of Credit Facility Swingline Loan Sublimit
Line of Credit Facility [Line Items]
Maximum borrowing capacity		25,000,000
Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity					$ 2,774,000,000.000
Credit facility		$ 0
Period for leverage ratio to determine interest rate spread		preceding four fiscal quarters
Interest expense		$ 9,700,000	42,900,000
Interest rate spread on overdue principal in event of default		2.00%
Interest rate spread on overdue amounts in event of default		2.00%
2020 Tranche | Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity		$ 3,122,000,000
February 2015 Amended Credit Facility with Maturity Dates of June 2018 and February 2020
Line of Credit Facility [Line Items]
Interest expense				$ 18,900,000
December 2015 Amended Credit Facility with Maturity Dates of June 2018 and February 2020
Line of Credit Facility [Line Items]
Debt issuance amortization		5,900,000	8,500,000
Credit facility		$ 0	$ 0
December 2015 Amended Credit Facility with Maturity Dates of June 2018 and February 2020 | Revolving Credit Facility
Line of Credit Facility [Line Items]
Total leverage ratio, maximum		5.00
Total consolidated debt, maximum		$ 700,000,000
Total leverage ratio, temporary maximum allowed, first four quarters		5.50
Total leverage ratio, temporary maximum allowed, next three quarters		5.25
Senior leverage ratio, maximum		3.50
Senior leverage ratio, minimum to obtain additional funding			2.50
Repayments of lines of credit	1,682,500,000
Debt issuance amortization	$ 2,100,000
Debt Instrument Interest Rate Option 2 | Revolving Credit Facility
Line of Credit Facility [Line Items]
Description of variable rate basis		adjusted LIBOR rate (based on one, two, three, or six-month interest periods)
Minimum | Debt Instrument Interest Rate Option 1 | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate		0.25%
Maximum | Debt Instrument Interest Rate Option 1 | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate		1.25%
Maximum | Debt Instrument Interest Rate Option 1 | February 2015 Amended Credit Facility with Maturity Dates of June 2018 and February 2020 | Line of Credit
Line of Credit Facility [Line Items]
Basis spread on variable rate		1.25%
Maximum | Debt Instrument Interest Rate Option 2 | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate		2.25%