Debt - Credit Facility (Details) - USD ($)	1 Months Ended		12 Months Ended
	Mar. 31, 2020	May 31, 2018	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018	Sep. 30, 2019	Jun. 30, 2019	Feb. 28, 2017
Line of Credit Facility [Line Items]
Debt issuance amortization	$ 67,900,000		$ 67,900,000	$ 83,600,000				$ 33,700,000
Revolving Credit Facility
Line of Credit Facility [Line Items]
Proceeds from borrowings on revolving loan under credit facility			1,026,000,000.0	4,416,500,000	$ 187,000,000.0
Term Loan Facility
Line of Credit Facility [Line Items]
Proceeds from borrowings on revolving loan under credit facility			0	3,000,000,000.0	$ 0
Line of Credit
Line of Credit Facility [Line Items]
Debt issuance amortization	3,900,000		3,900,000
Line of Credit | Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum amount to finance Convertible Notes	1,000,000,000.0		1,000,000,000.0
Maximum borrowing capacity	3,570,000,000		3,570,000,000			$ 3,570,000,000	$ 3,600,000,000
Debt issuance amortization	14,600,000		14,600,000	14,700,000
Extinguishment of debt, amount				244,300,000
Restrictive covenants, maximum transfer or assignment of securitization assets						$ 600,000,000
Line of credit facility covenant, total indebtedness, convertible debt excluded, maximum	$ 700,000,000		$ 700,000,000
Interest coverage ratio, less than	3.25		3.25
Interest rate spread on overdue principal in event of default	2.00%		2.00%
Interest rate spread on overdue amounts in event of default	2.00%		2.00%
Line of Credit | Revolving Credit Facility | Leverage Ratio Percent One
Line of Credit Facility [Line Items]
Line of credit facility, covenant, total leverage ratio, maximum	6.00		6.00
Total leverage ratio, temporary maximum allowed, next three quarters	4.75		4.75
Line of Credit | Revolving Credit Facility | Leverage Ratio Percent Two
Line of Credit Facility [Line Items]
Line of credit facility, covenant, total leverage ratio, maximum	5.75		5.75
Total leverage ratio, temporary maximum allowed, next three quarters	4.25		4.25
Line of Credit | Revolving Credit Facility | Leverage Ratio Percent Three
Line of Credit Facility [Line Items]
Line of credit facility, covenant, total leverage ratio, maximum	5.25		5.25
Total leverage ratio, temporary maximum allowed, next three quarters	3.75		3.75
Line of Credit | Revolving Credit Facility | Minimum | Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.00%		0.00%
Line of Credit | Revolving Credit Facility | Minimum | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.00%		1.00%
Line of Credit | Revolving Credit Facility | Maximum | Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.75%		0.75%
Line of Credit | Revolving Credit Facility | Maximum | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.75%		1.75%
Line of Credit | Revolving Credit Facility | 2023 Tranche
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 3,570,000,000		$ 3,570,000,000
Line of Credit | Foreign Line of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity	250,000,000.0		250,000,000.0
Line of Credit | Standby Letters of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity	50,000,000.0		50,000,000.0
Line of Credit | Line of Credit Facility Swingline Loan Sublimit
Line of Credit Facility [Line Items]
Maximum borrowing capacity	25,000,000.0		25,000,000.0
Line of Credit | Term Loan Facility
Line of Credit Facility [Line Items]
Debt issuance amortization	$ 14,600,000	$ 34,700,000	14,600,000	19,400,000
Proceeds from borrowings on loan facility		$ 3,000,000,000.0
Quarterly amortization payments, percent		0.25%
Repayments of long-term debt			188,000,000.0	1,090,000,000.00
Loss on settlement of debt			$ 1,900,000	11,500,000
Proceeds from borrowings on revolving loan under credit facility				$ 500,000,000.0
Line of Credit | Term Loan Facility | Leverage Ratio Percent One
Line of Credit Facility [Line Items]
Mandatory prepayment of excess cash flow, percentage	50.00%		50.00%
Line of Credit | Term Loan Facility | Leverage Ratio Percent Two
Line of Credit Facility [Line Items]
Mandatory prepayment of excess cash flow, percentage	25.00%		25.00%
Line of Credit | Term Loan Facility | Leverage Ratio Percent Three
Line of Credit Facility [Line Items]
Mandatory prepayment of excess cash flow, percentage	0.00%		0.00%