CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions		3 Months Ended		6 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Net sales		$ 1,309.5	$ 1,337.8	$ 2,619.2	$ 2,660.4
Cost of sales	[1]	501.6	510.3	1,013.0	1,017.7
Gross profit		807.9	827.5	1,606.2	1,642.7
Research and development	[1]	199.8	219.8	397.8	438.9
Selling, general and administrative	[1]	144.7	172.3	291.0	340.2
Amortization of acquired intangible assets		232.9	248.2	468.3	496.7
Special charges and other, net		4.3	3.6	4.6	11.7
Operating expenses		581.7	643.9	1,161.7	1,287.5
Operating income		226.2	183.6	444.5	355.2
Other income (expense):
Interest income		0.3	1.0	0.6	1.7
Interest expense		(93.3)	(129.6)	(192.4)	(262.2)
Loss on settlement of debt		(45.1)	(0.1)	(71.9)	(2.0)
Other income (loss), net		0.7	(1.4)	(2.5)	1.3
Income before income taxes		88.8	53.5	178.3	94.0
Income tax provision (benefit)		15.2	(55.4)	(18.9)	(65.6)
Net income		$ 73.6	$ 108.9	$ 197.2	$ 159.6
Basic net income per common share (in dollars per share)		$ 0.29	$ 0.46	$ 0.78	$ 0.67
Diluted net income per common share (in dollars per share)		0.27	0.43	0.75	0.63
Dividends declared per common share (in dollars per share)		$ 0.3680	$ 0.3660	$ 0.7355	$ 0.7315
Basic common shares outstanding (in shares)		256.0	238.4	251.9	238.1
Diluted common shares outstanding (in shares)		267.7	255.3	262.8	254.6

[1] (1) Includes share-based compensation expense as follows: Cost of sales$6.0 $5.2 $12.4 $10.1 Research and development$24.5 $22.3 $45.0 $41.8 Selling, general and administrative$19.2 $17.8 $34.7 $34.1