CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Net sales	$ 1,352.1	$ 1,287.4	$ 3,971.3	$ 3,947.8
Cost of sales	506.3	501.9	1,519.3	1,519.6
Gross profit	845.8	785.5	2,452.0	2,428.2
Research and development	210.1	217.1	607.9	656.0
Selling, general and administrative	154.2	170.7	445.2	510.9
Amortization of acquired intangible assets	231.6	248.7	699.9	745.4
Special charges and other, net	4.3	17.8	8.9	29.5
Operating expenses	600.2	654.3	1,761.9	1,941.8
Operating income	245.6	131.2	690.1	486.4
Other income (expense):
Interest income	0.2	0.6	0.8	2.3
Interest expense	(86.5)	(119.7)	(278.9)	(381.9)
Loss on settlement of debt	(142.1)	0.0	(214.0)	(2.0)
Other loss, net	(0.4)	(1.5)	(2.9)	(0.2)
Income before income taxes	16.8	10.6	195.1	104.6
Income tax benefit	(19.4)	(300.5)	(38.3)	(366.1)
Net income	$ 36.2	$ 311.1	$ 233.4	$ 470.7
Basic net income per common share (in dollars per share)	$ 0.14	$ 1.30	$ 0.91	$ 1.97
Diluted net income per common share (in dollars per share)	0.13	1.20	0.87	1.84
Dividends declared per common share (in dollars per share)	$ 0.3685	$ 0.3665	$ 1.1040	$ 1.0980
Basic common shares outstanding (in shares)	263.4	239.2	255.7	238.5
Diluted common shares outstanding (in shares)	275.4	258.3	267.0	255.8