Consolidated Statements of Income and Comprehensive Income - USD ($) shares in Millions, $ in Millions	12 Months Ended
	May 31, 2018		May 31, 2017		May 31, 2016
Revenue:
Service revenue	$ 3,317.4		$ 3,100.7		$ 2,905.8
Interest on funds held for clients	63.5		50.6		46.1
Total revenue	3,380.9		3,151.3		2,951.9
Expenses:
Operating expenses	1,017.8		919.6		857.1
Selling, general and administrative expenses	1,075.6		992.1		948.2
Total expenses	2,093.4		1,911.7		1,805.3
Operating income	1,287.5		1,239.6		1,146.6
Investment income, net	8.6		5.2		4.5
Income before income taxes	1,296.1		1,244.8		1,151.1
Income taxes	362.4	[1]	427.5		394.3
Net income	933.7		817.3		756.8
Other comprehensive (loss)/income, net of tax	(56.2)		(9.2)		21.7
Comprehensive income	$ 877.5		$ 808.1		$ 778.5
Basic earnings per share	$ 2.60	[2]	$ 2.27	[2]	$ 2.10
Diluted earnings per share	$ 2.58	[2]	$ 2.25	[2]	$ 2.09
Weighted-average common shares outstanding	359.0		359.8		360.7
Weighted-average common shares outstanding, assuming dilution	361.5		362.6		362.5
Cash dividends per common share	$ 2.06		$ 1.84		$ 1.68

[1] As a result of the Tax Act, the effective income tax rate for the three months ended February 28, 2018 was significantly impacted by certain one-time net tax benefits. Refer to Note K for further details.

[2] Each quarter is a discrete period and the sum of the four quarters' basic and diluted earnings per share amounts may not equal the full year amount.