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)								14
Stock options exercised	419	419
Conversion to Class B Common Stock (in shares)						(14)		14
Conversion to Class B Common Stock	0
Repurchase of Class B Common Stock (in shares)								(44)
Repurchase of Class B Common Stock	(3,386)	(181)		(3,205)
Dividends on common stock and preferred stock	(1,013)			(1,013)
Issuance of shares to employees, net of shares withheld for employee taxes (in shares)								2
Issuance of shares to employees, net of shares withheld for employee taxes	58	62		(4)
Stock-based compensation	226	226
Net income	3,040			3,040
Other comprehensive income (loss)	289		289
Ending Balance (in shares) at Feb. 28, 2019						315		1,258
Ending balance at Feb. 28, 2019	8,961	6,910	197	1,851		$ 0		$ 3
Beginning Balance (in shares) at Nov. 30, 2018						315		1,262
Beginning balance at Nov. 30, 2018	8,729	6,707	209	1,810		$ 0		$ 3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised (in shares)								6
Stock options exercised	159	159
Repurchase of Class B Common Stock (in shares)								(10)
Repurchase of Class B Common Stock	(754)	(44)		(710)
Dividends on common stock and preferred stock	(347)			(347)
Issuance of shares to employees, net of shares withheld for employee taxes	(8)	(5)		(3)
Stock-based compensation	93	93
Net income	1,101			1,101
Other comprehensive income (loss)	(12)		(12)
Ending Balance (in shares) at Feb. 28, 2019						315		1,258
Ending balance at Feb. 28, 2019	8,961	6,910	197	1,851		$ 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)								17
Stock options exercised	580	580
Repurchase of Class B Common Stock (in shares)								(32)
Repurchase of Class B Common Stock	(2,874)	(150)		(2,724)
Dividends on common stock and preferred stock	(1,110)			(1,110)
Issuance of shares to employees, net of shares withheld for employee taxes (in shares)								2
Issuance of shares to employees, net of shares withheld for employee taxes	66	75		(9)
Stock-based compensation	303	303
Net income	3,329			3,329
Other comprehensive income (loss)	(288)		(288)
Ending Balance (in shares) at Feb. 29, 2020					315	315	1,240	1,240
Ending balance at Feb. 29, 2020	9,045	7,971	(57)	1,128		$ 0		$ 3
Beginning Balance (in shares) at Nov. 30, 2019						315		1,244
Beginning balance at Nov. 30, 2019	9,351	7,719	52	1,577		$ 0		$ 3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised (in shares)								6
Stock options exercised	199	199
Repurchase of Class B Common Stock (in shares)								(10)
Repurchase of Class B Common Stock	(957)	(48)		(909)
Dividends on common stock and preferred stock	(383)			(383)
Issuance of shares to employees, net of shares withheld for employee taxes	(16)	(12)		(4)
Stock-based compensation	113	113
Net income	847			847
Other comprehensive income (loss)	(109)		(109)
Ending Balance (in shares) at Feb. 29, 2020					315	315	1,240	1,240
Ending balance at Feb. 29, 2020	$ 9,045	$ 7,971	$ (57)	$ 1,128		$ 0		$ 3