Consolidated Statements of Shareholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Capital in Excess of Stated Value	Accumulated Other Comprehensive Income	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, 2013						356		1,433
Beginning Balance at May. 31, 2013	$ 11,081	$ 5,184	$ 274	$ 5,620		$ 0		$ 3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised (in shares)								22
Stock options exercised	445	445
Conversion to Class B Common Stock (in shares)						(1)		1
Conversion to Class B Common Stock	0
Repurchase of Class B Common Stock (in shares)								(73)
Repurchase of Class B Common Stock	(2,628)	(11)		(2,617)
Dividends on Common stock	(821)			(821)
Issuance of shares to employees (in shares)								3
Issuance of shares to employees	78	78
Stock-based compensation	177	177
Forfeiture of shares from employees (in shares)								(1)
Forfeiture of shares from employees	(12)	(8)		(4)
Net income	2,693			2,693
Other comprehensive income (loss)	(189)		(189)
Ending Balance (in shares) at May. 31, 2014						355		1,385
Ending Balance at May. 31, 2014	10,824	5,865	85	4,871		$ 0		$ 3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised (in shares)								27
Stock options exercised	639	639
Repurchase of Class B Common Stock (in shares)								(58)
Repurchase of Class B Common Stock	(2,534)	(9)		(2,525)
Dividends on Common stock	(931)			(931)
Issuance of shares to employees (in shares)								3
Issuance of shares to employees	92	92
Stock-based compensation	191	191
Forfeiture of shares from employees (in shares)								0
Forfeiture of shares from employees	(8)	(5)		(3)
Net income	3,273			3,273
Other comprehensive income (loss)	1,161		1,161
Ending Balance (in shares) at May. 31, 2015					355	355	1,357	1,357
Ending Balance at May. 31, 2015	12,707	6,773	1,246	4,685		$ 0		$ 3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised (in shares)								22
Stock options exercised	680	680
Conversion to Class B Common Stock (in shares)						(2)		2
Conversion to Class B Common Stock	0
Repurchase of Class B Common Stock (in shares)								(55)
Repurchase of Class B Common Stock	(3,238)	(8)		(3,230)
Dividends on Common stock	(1,053)			(1,053)
Issuance of shares to employees (in shares)								3
Issuance of shares to employees	115	115
Stock-based compensation	236	236
Forfeiture of shares from employees (in shares)								0
Forfeiture of shares from employees	(21)	(10)		(11)
Net income	3,760			3,760
Other comprehensive income (loss)	(928)		(928)
Ending Balance (in shares) at May. 31, 2016					353	353	1,329	1,329
Ending Balance at May. 31, 2016	$ 12,258	$ 7,786	$ 318	$ 4,151		$ 0		$ 3