CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	9 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net income	$ 233,400,000	$ 470,700,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	865,500,000	904,700,000
Deferred income taxes	(82,900,000)	(404,200,000)
Share-based compensation expense related to equity incentive plans	143,300,000	129,500,000
Loss on settlement of debt	214,000,000.0	2,000,000.0
Amortization of debt discount	57,500,000	90,900,000
Amortization of debt issuance costs	13,200,000	12,800,000
(Gains) losses on sale of assets	(900,000)	400,000
Impairment of intangible assets	0	500,000
Gains on equity investments	(200,000)	(1,000,000.0)
Other non-cash adjustment	900,000	2,700,000
Changes in operating assets and liabilities, excluding impact of acquisitions:
Decrease in accounts receivable	40,200,000	73,200,000
Decrease in inventories	17,500,000	5,600,000
Increase (decrease) in accounts payable and accrued liabilities	6,600,000	(53,300,000)
Change in other assets and liabilities	(23,300,000)	(3,900,000)
Change in income tax payable	(17,500,000)	(58,500,000)
Net cash provided by operating activities	1,467,300,000	1,172,100,000
Cash flows from investing activities:
Purchases of available-for-sale investments	0	(2,000,000.0)
Investments in other assets	(73,100,000)	(40,500,000)
Proceeds from sale of assets	200,000	500,000
Capital expenditures	(37,200,000)	(55,700,000)
Net cash used in investing activities	(110,100,000)	(97,700,000)
Cash flows from financing activities:
Payments on settlement of convertible debt	(2,252,200,000)	0
Proceeds from issuance of senior notes	3,577,800,000	0
Repayment of bridge loan facility	(615,000,000.0)	0
Deferred financing costs	(18,300,000)	(1,800,000)
Purchase of capped call options	(35,800,000)	0
Payment of cash dividends	(281,700,000)	(262,100,000)
Proceeds from sale of common stock	40,200,000	38,800,000
Tax payments related to shares withheld for vested restricted stock units	(46,500,000)	(50,200,000)
Capital lease payments	(600,000)	(600,000)
Net cash used in financing activities	(1,387,500,000)	(1,105,900,000)
Net decrease in cash and cash equivalents	(30,300,000)	(31,500,000)
Cash and cash equivalents, and restricted cash at beginning of period	401,000,000.0	428,600,000
Cash and cash equivalents, and restricted cash at end of period	370,700,000	397,100,000
Term Loan Facility
Cash flows from financing activities:
Repayments of loan facility	(1,723,500,000)	(188,000,000.0)
Revolving Credit Facility
Cash flows from financing activities:
Repayments of loan facility	(3,104,900,000)	(1,324,000,000.0)
Proceeds from borrowings on revolving loan under credit facility	$ 3,073,000,000.0	$ 682,000,000.0