Consolidated Statements of Shareholders' Equity (USD $) In Millions, unless otherwise specified	Total USD ($)	Capital in Excess of Stated Value USD ($)	Accumulated Other Comprehensive Income USD ($)	Retained Earnings USD ($)	Common Stock Class A	Common Stock Class A Common Stock USD ($)	Class B Common Stock	Class B Common Stock Common Stock USD ($)
Beginning Balance at May. 31, 2011	$ 9,793	$ 3,944	$ 95	$ 5,751		$ 0		$ 3
Beginning Balance (in shares) at May. 31, 2011						180		756
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised (in shares)								18.0
Stock options exercised	528	528
Repurchase of Class B Common Stock	(1,805)	(12)		(1,793)
Repurchase of Class B Common Stock (in shares)								(40)
Dividends on Common stock	(639)			(639)
Issuance of shares to employees (in shares)								2
Issuance of shares to employees	57	57
Stock-based compensation (Note 11)	130	130
Forfeiture of shares from employees (in shares)								0
Forfeiture of shares from employees	(10)	(6)		(4)
Net income	2,211			2,211
Other comprehensive income	54		54
Ending Balance at May. 31, 2012	10,319	4,641	149	5,526		0		3
Ending Balance (in shares) at May. 31, 2012						180		736
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised (in shares)								10.0
Stock options exercised	322	322
Conversion of Stock, Shares Converted						(2)		2
Repurchase of Class B Common Stock	(1,657)	(10)		(1,647)
Repurchase of Class B Common Stock (in shares)								(34)
Dividends on Common stock	(727)			(727)
Issuance of shares to employees (in shares)								2
Issuance of shares to employees	65	65
Stock-based compensation (Note 11)	174	174
Forfeiture of shares from employees (in shares)								0
Forfeiture of shares from employees	(12)	(8)		(4)
Net income	2,472			2,472
Other comprehensive income	125		125
Ending Balance at May. 31, 2013	11,081	5,184	274	5,620		0		3
Ending Balance (in shares) at May. 31, 2013					178	178	716	716
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised (in shares)								11.0
Stock options exercised	445	445
Repurchase of Class B Common Stock	(2,628)	(11)		(2,617)
Repurchase of Class B Common Stock (in shares)								(37)
Dividends on Common stock	(821)			(821)
Issuance of shares to employees (in shares)								2
Issuance of shares to employees	78	78
Stock-based compensation (Note 11)	177	177
Forfeiture of shares from employees (in shares)								0
Forfeiture of shares from employees	(12)	(8)		(4)
Net income	2,693			2,693
Other comprehensive income	(189)		(189)
Ending Balance at May. 31, 2014	$ 10,824	$ 5,865	$ 85	$ 4,871		$ 0		$ 3
Ending Balance (in shares) at May. 31, 2014					178	178	692	692