CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Millions	Total	Adjustment	Common Stock and Additional Paid-in-Capital	Common Stock and Additional Paid-in-Capital Adjustment	Common Stock Held in Treasury	Accumulated Other Comprehensive Loss	Retained Earnings	Retained Earnings Adjustment
Balance, common stock shares issued (in shares) at Mar. 31, 2021			569,000,000.0
Beginning balance at Mar. 31, 2021	$ 5,337.1		$ 2,403.6		$ (433.8)	$ (26.2)	$ 3,393.5
Beginning balance, common stock held in treasury (in shares) at Mar. 31, 2021					21,900,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,285.5						1,285.5
Other comprehensive income	5.6					5.6
Proceeds from sales of common stock through employee equity incentive plans (shares)			5,400,000
Proceeds from sales of common stock through employee equity incentive plans	70.5		$ 70.5
RSU withholdings (shares)			(1,200,000)
RSU withholdings	(84.2)		$ (84.2)
Treasury stock used for new issuances (shares)			(4,200,000)		(4,200,000)
Treasury stock used for new issuances	$ 0.0		$ (63.1)		$ 63.1
Repurchase of common stock (in shares)	5,600,000				5,600,000
Repurchase of common stock	$ (425.6)				$ (425.6)
Shares issued to settle convertible debt	670.7		$ 670.7
Shares issued to settle convertible debt (in shares)			8,800,000
Settlement of convertible debt	(668.5)		$ (668.5)
Share-based compensation	207.5		$ 207.5
Cash dividend	(503.8)						(503.8)
Balance, common stock shares issued (in shares) at Mar. 31, 2022			577,800,000
Ending balance at Mar. 31, 2022	5,894.8		$ 2,536.5		$ (796.3)	(20.6)	4,175.2
Ending balance (Accounting Standards Update 2020-06) at Mar. 31, 2022		$ (81.8)		$ (128.3)				$ 46.5
Ending balance, common stock held in treasury (in shares) at Mar. 31, 2022					23,300,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,237.7						2,237.7
Other comprehensive income	16.5					16.5
Proceeds from sales of common stock through employee equity incentive plans (shares)			4,900,000
Proceeds from sales of common stock through employee equity incentive plans	82.3		$ 82.3
RSU withholdings (shares)			(1,000,000.0)
RSU withholdings	(75.8)		$ (75.8)
Treasury stock used for new issuances (shares)			(3,900,000)		(3,900,000)
Treasury stock used for new issuances	$ 0.0		$ (81.9)		$ 81.9
Repurchase of common stock (in shares)	12,900,000				12,900,000
Repurchase of common stock	$ (945.8)				$ (945.8)
Settlement of convertible debt	(91.1)		(91.1)
Share-based compensation	172.1		$ 172.1
Cash dividend	$ (695.3)						(695.3)
Balance, common stock shares issued (in shares) at Mar. 31, 2023	577,805,623		577,800,000
Ending balance at Mar. 31, 2023	$ 6,513.6		$ 2,413.8		$ (1,660.2)	(4.1)	5,764.1
Ending balance, common stock held in treasury (in shares) at Mar. 31, 2023	32,345,809				32,300,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 1,906.9						1,906.9
Other comprehensive income	0.6					0.6
Proceeds from sales of common stock through employee equity incentive plans (shares)			4,000,000.0
Proceeds from sales of common stock through employee equity incentive plans	82.1		$ 82.1
RSU withholdings (shares)			(900,000)
RSU withholdings	(61.1)		$ (61.1)
Treasury stock used for new issuances (shares)			(3,100,000)		(3,100,000)
Treasury stock used for new issuances	$ 0.0		$ (67.5)		$ 67.5
Repurchase of common stock (in shares)	11,900,000				11,900,000
Repurchase of common stock	$ (988.9)				$ (988.9)
Settlement of convertible debt	(65.3)		(65.3)
Share-based compensation	181.4		$ 181.4
Cash dividend	$ (911.5)						(911.5)
Balance, common stock shares issued (in shares) at Mar. 31, 2024	577,806,659		577,800,000
Ending balance at Mar. 31, 2024	$ 6,657.8		$ 2,483.4		$ (2,581.6)	$ (3.5)	$ 6,759.5
Ending balance, common stock held in treasury (in shares) at Mar. 31, 2024	41,142,968				41,100,000