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	Restatement Adjustment	Restatement Adjustment RETAINED EARNINGS
Beginning Balance (in shares) at May. 31, 2016						353		1,329
Beginning balance at May. 31, 2016	$ 12,258	$ 5,038	$ 318	$ 6,899		$ 0		$ 3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised (in shares)								17
Stock options exercised	525	525
Conversion to Class B Common Stock (in shares)						(24)		24
Conversion to Class B Common Stock	0
Repurchase of class B common stock (in shares)								(60)
Repurchase of Class B Common Stock	(3,249)	(189)		(3,060)
Dividends on common stock and preferred stock	(1,159)			(1,159)
Issuance of shares to employees, net of shares withheld for employee taxes (in shares)								4
Issuance of shares to employees, net of shares withheld for employee taxes	108	121		(13)
Stock-based compensation	215	215
Net income	4,240			4,240
Other comprehensive income (loss)	(531)		(531)
Ending Balance (in shares) at May. 31, 2017						329		1,314
Ending balance at May. 31, 2017	12,407	5,710	(213)	6,907		$ 0		$ 3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised (in shares)								24
Stock options exercised	600	600
Repurchase of class B common stock (in shares)								(70)
Repurchase of Class B Common Stock	(4,267)	(254)		(4,013)
Dividends on common stock and preferred stock	(1,265)			(1,265)
Issuance of shares to employees, net of shares withheld for employee taxes (in shares)								4
Issuance of shares to employees, net of shares withheld for employee taxes	82	110		(28)
Stock-based compensation	218	218
Net income	1,933			1,933
Other comprehensive income (loss)	104		104
Ending Balance (in shares) at May. 31, 2018					329	329	1,272	1,272
Ending 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)								18
Stock options exercised	539	539
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)								(54)
Repurchase of Class B Common Stock	(4,283)	(227)		(4,056)
Dividends on common stock and preferred stock	(1,360)			(1,360)
Issuance of shares to employees, net of shares withheld for employee taxes (in shares)								3
Issuance of shares to employees, net of shares withheld for employee taxes	139	142		(3)
Stock-based compensation	325	325
Net income	4,029			4,029
Other comprehensive income (loss)	323		323
Ending Balance (in shares) at May. 31, 2019					315	315	1,253	1,253
Ending balance at May. 31, 2019	$ 9,040	$ 7,163	$ 231	$ 1,643		$ 0		$ 3
Ending balance (Adoption of ASU 2016-16 (Note 1)) at May. 31, 2019									$ (507)	$ (507)
Ending balance (Adoption of ASC Topic 606 (Note 1)) at May. 31, 2019									$ 23	$ 23