Basic and Diluted Earnings Per Share (Basic and Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Aug. 31, 2023	Aug. 31, 2022
Basic earnings per share:
Net income	$ 419.2	$ 379.2
Weighted-average common shares outstanding	360.8	360.1
Basic earnings per share	$ 1.16	$ 1.05
Diluted earnings per share:
Net income	$ 419.2	$ 379.2
Weighted-average common shares outstanding	360.8	360.1
Dilutive effect of common share equivalents	2.0	2.3
Weighted-average common shares outstanding, assuming dilution	362.8	362.4
Diluted earnings per share	$ 1.16	$ 1.05
Weighted-average anti-dilutive common share equivalents	0.6	0.4