Basic and Diluted Earnings Per Share (Basic and Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	May 31, 2021	May 31, 2020	May 31, 2019
Basic earnings per share:
Net income	$ 1,097.5	$ 1,098.1	$ 1,034.4
Weighted-average common shares outstanding	359.9	358.5	359.2
Basic earnings per share	$ 3.05	$ 3.06	$ 2.88
Diluted earnings per share:
Net income	$ 1,097.5	$ 1,098.1	$ 1,034.4
Weighted-average common shares outstanding	359.9	358.5	359.2
Dilutive effect of common share equivalents	2.2	2.5	2.6
Weighted-average common shares outstanding, assuming dilution	362.1	361.0	361.8
Diluted earnings per share	$ 3.03	$ 3.04	$ 2.86
Weighted-average anti-dilutive common share equivalents	0.6	0.7	0.4