v2.4.0.6
Investments - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Jul. 28, 2012
Schedule of Available-for-sale Securities [Line Items]  
Proceeds from the sale of the investment portfolio $ 240
Realized gain on the sale of investment 1
Available-for-sale investments - non-current | Auction rate securities
 
Schedule of Available-for-sale Securities [Line Items]  
Non investment ARS remaining with book value 2.7
Non investment ARS remaining with par value 3.9
Available-for-sale investments, called for redemption $ 11.7