Current Liabilities (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jul. 31, 2012	Feb. 17, 2012	Jul. 31, 2011	Mar. 12, 2007
Current Liabilities (Textuals)
Debt instrument, face amount	$ 500		$ 1,000	$ 1,000
Unsecured revolving credit facility		500
Maximum ratio of debt to annual earnings before interest, taxes, depreciation and amortization as per agreement	3.25
Minimum ratio of annual earnings before interest, taxes, depreciation and amortization to interest payable as per agreement	3.00
Letters of credit outstanding, amount	0
Other Current Liabilities
Reserve for product returns	19		20
Reserve for rebates	17		11
Current portion of license fee payable	10		10
Current portion of deferred rent	8		7
Interest payable	10		21
Executive deferred compensation plan liabilities	56		50
Other	24		22
Total other current liabilities	144		141
5.40 percent fixed-rate notes due 2012 [Member]
Current Liabilities (Textuals)
Debt instrument, face amount	$ 0		$ 500
Senior notes, rate				5.40%
JP Morgan Alternate Base [Member] | Minimum [Member]
Current Liabilities (Textuals)
Libor plus variable interest rate on advances under credit facilities	0.00%
JP Morgan Alternate Base [Member] | Maximum [Member]
Current Liabilities (Textuals)
Libor plus variable interest rate on advances under credit facilities	0.50%
LIBOR [Member] | Minimum [Member]
Current Liabilities (Textuals)
Libor plus variable interest rate on advances under credit facilities		0.90%
LIBOR [Member] | Maximum [Member]
Current Liabilities (Textuals)
Libor plus variable interest rate on advances under credit facilities		1.50%