Statements of Consolidated Shareholders' Equity - USD ($) $ in Millions		Total	Common Shares	Additional Capital	Retained Income	Accumulated Other Comprehensive Income (Loss)
Balance at Apr. 30, 2017		$ 6,850.2	$ 28.4	$ 5,724.7	$ 1,240.5	$ (143.4)
Balance, shares at Apr. 30, 2017			113,439,553
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		1,338.6			1,338.6
Other comprehensive income (loss)		41.7				41.7
Comprehensive Income		1,380.3
Purchase of treasury shares		(7.0)	$ 0.0	(5.8)	(1.2)
Purchase of treasury shares, shares			(54,535)
Stock plans		21.3	$ 0.0	21.3
Stock plans, shares			187,822
Cash dividends declared		(353.7)			(353.7)
Reclassification of stranded tax effects	[1]	0.0			15.0	(15.0)	[2]
Other		0.0	$ 0.5	(0.5)
Balance at Apr. 30, 2018		7,891.1	$ 28.9	5,739.7	2,239.2	(116.7)
Balance, shares at Apr. 30, 2018			113,572,840
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		514.4			514.4
Other comprehensive income (loss)		(65.1)				(65.1)
Comprehensive Income		449.3
Purchase of treasury shares		(5.4)	$ 0.0	(5.4)	0.0
Purchase of treasury shares, shares			(50,723)
Stock plans		21.5	$ 0.0	21.5
Stock plans, shares			220,179
Cash dividends declared		(386.0)			(386.0)
Other		0.0	$ 0.0		0.0
Balance at Apr. 30, 2019		$ 7,970.5	$ 28.9	5,755.8	2,367.6	(181.8)
Balance, shares at Apr. 30, 2019		113,742,296	113,742,296
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		$ 779.5			779.5
Other comprehensive income (loss)		(197.2)				(197.2)
Comprehensive Income		582.3
Purchase of treasury shares		(4.2)	$ 0.0	(4.3)	0.1
Purchase of treasury shares, shares			(35,588)
Stock plans		42.7	$ 0.1	42.6
Stock plans, shares			366,018
Cash dividends declared		(400.4)			(400.4)
Other		0.0			0.0
Balance at Apr. 30, 2020		$ 8,190.9	$ 29.0	$ 5,794.1	$ 2,746.8	$ (379.0)
Balance, shares at Apr. 30, 2020		114,072,726	114,072,726

[1] During 2018, we elected to early adopt Accounting Standards Update (“ASU”) 2018-02, Income Statement – Reporting Comprehensive Income (Topic 220) Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income, which allowed us to reclassify the stranded income tax effects resulting from the U.S. Tax Cuts and Jobs Act (the “Tax Act”) from accumulated other comprehensive income (loss) to retained earnings.

[2] During 2018, we adopted ASU 2018-02, Income Statement – Reporting Comprehensive Income (Topic 220) Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income, which allowed us to reclassify the stranded income tax effects resulting from the Tax Act from accumulated other comprehensive income (loss) to retained earnings.