Consolidated Statements of Shareholders' Equity (USD $) In Millions, unless otherwise specified	Total	Common Stock Class A	Common Stock Class B	Capital in Excess of Stated Value	Accumulated Other Comprehensive Income	Retained Earnings
Beginning Balance at May. 31, 2010	$ 9,754	$ 0	$ 3	$ 3,441	$ 215	$ 6,095
Beginning Balance (in shares) at May. 31, 2010		180	788
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised (in shares)			14.0
Stock options exercised	368			368
Repurchase of Class B Common Stock	(1,871)			(14)		(1,857)
Repurchase of Class B Common Stock (in shares)			(48)
Dividends on Common stock	(569)					(569)
Issuance of shares to employees (in shares)			2
Issuance of shares to employees	49			49
Stock-based compensation (Note 11)	105			105
Forfeiture of shares from employees (in shares)			0
Forfeiture of shares from employees	(6)			(5)		(1)
Net income	2,133					2,133
Other comprehensive income	(120)				(120)
Ending Balance at May. 31, 2011	9,843	0	3	3,944	95	5,801
Ending 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	2,223					2,223
Other comprehensive income	54				54
Ending Balance at May. 31, 2012	10,381	0	3	4,641	149	5,588
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	0	(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	2,485					2,485
Other comprehensive income	125				125
Ending Balance at May. 31, 2013	$ 11,156	$ 0	$ 3	$ 5,184	$ 274	$ 5,695
Ending Balance (in shares) at May. 31, 2013		178	716