CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Net sales		$ 1,287.4	$ 1,374.7	$ 3,947.8	$ 4,019.7
Cost of sales	[1]	501.9	595.1	1,519.6	1,908.8
Gross profit		785.5	779.6	2,428.2	2,110.9
Research and development	[1]	217.1	217.7	656.0	611.6
Selling, general and administrative	[1]	170.7	174.8	510.9	515.5
Amortization of acquired intangible assets		248.7	193.7	745.4	497.2
Special charges (income) and other, net	[1]	17.8	(1.3)	29.5	57.0
Operating expenses		654.3	584.9	1,941.8	1,681.3
Operating income		131.2	194.7	486.4	429.6
Losses on equity method investments		0.0	(0.1)	0.0	(0.2)
Other income (expense):
Interest income		0.6	0.7	2.3	7.3
Interest expense		(119.7)	(137.6)	(381.9)	(366.7)
Loss on settlement of debt		0.0	(0.2)	(2.0)	(4.3)
Other loss, net		(1.5)	(2.5)	(0.2)	(12.4)
Income before income taxes		10.6	55.0	104.6	53.3
Income tax (benefit) provision		(300.5)	5.8	(366.1)	(127.9)
Net Income		$ 311.1	$ 49.2	$ 470.7	$ 181.2
Basic net income per common share (in dollars per share)		$ 1.30	$ 0.21	$ 1.97	$ 0.77
Diluted net income per common share (in dollars per share)		1.20	0.20	1.84	0.73
Dividends declared per common share (in dollars per share)		$ 0.3665	$ 0.3645	$ 1.0980	$ 1.0920
Basic common shares outstanding (in shares)		239.2	236.7	238.5	235.9
Diluted common shares outstanding (in shares)		258.3	244.6	255.8	249.5

[1] Three Months Ended December 31, Nine Months EndedDecember 31,(1) Includes share-based compensation expense as follows:2019 2018 2019 2018Cost of sales$5.7 $3.4 $15.8 $10.9Research and development$21.2 $19.4 $63.0 $53.2Selling, general and administrative$16.6 $16.6 $50.7 $46.1Special charges and other, net$— $0.2 $— $17.3