Unaudited Condensed Consolidated Statements of Shareholders' Equity - USD ($) shares in Millions, $ in Millions	Total	CAPITAL IN EXCESS OF STATED VALUE	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	RETAINED EARNINGS	Class A Common Stock	Class A Common Stock COMMON STOCK	Class B Common Stock	Class B Common Stock COMMON STOCK
Beginning Balance (in shares) at May. 31, 2018						329		1,272
Beginning balance at May. 31, 2018	$ 9,812	$ 6,384	$ (92)	$ 3,517		$ 0		$ 3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised (in shares)								6
Stock options exercised	182	182
Conversion to Class B Common Stock (in shares)						(9)		9
Conversion to Class B Common Stock	0
Repurchase of class B common stock (in shares)								(18)
Repurchase of Class B Common Stock	(1,381)	(69)		(1,312)
Dividends on common stock and preferred stock	(318)			(318)
Issuance of shares to employees, net of shares withheld for employee taxes	(14)	(13)		(1)
Stock-based compensation	41	41
Net income	1,092			1,092
Other comprehensive income (loss)	62		62
Ending Balance (in shares) at Aug. 31, 2018						320		1,269
Ending balance at Aug. 31, 2018	8,992	6,525	(30)	2,494		$ 0		$ 3
Beginning Balance (in shares) at May. 31, 2019					315	315	1,253	1,253
Beginning balance at May. 31, 2019	9,040	7,163	231	1,643		$ 0		$ 3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised (in shares)								4
Stock options exercised	116	116
Conversion to Class B Common Stock	0
Repurchase of class B common stock (in shares)								(12)
Repurchase of Class B Common Stock	(995)	(55)		(940)
Dividends on common stock and preferred stock	(344)			(344)
Issuance of shares to employees, net of shares withheld for employee taxes	(12)	(8)		(4)
Stock-based compensation	80	80
Net income	1,367			1,367
Other comprehensive income (loss)	(51)		(51)
Ending Balance (in shares) at Aug. 31, 2019					315	315	1,245	1,245
Ending balance at Aug. 31, 2019	$ 9,200	$ 7,296	$ 180	$ 1,721		$ 0		$ 3