Financial Instruments and Fair Value - Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis by Balance Sheet Grouping (Detail) (USD $) In Millions, unless otherwise specified	Oct. 26, 2012
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	$ 541.6
Short-term investments	3,754.2
Other current assets	8.9
Other non-current assets	66.6
Total	4,371.3
Other current liabilities	1.8
Fair Value, Inputs, Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	481.6
Short-term investments	203.6
Other current assets	6.0
Other non-current assets	20.1
Total	711.3
Other current liabilities	0
Fair Value, Inputs, Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	60.0
Short-term investments	3,550.6
Other current assets	2.9
Other non-current assets	0
Total	3,613.5
Other current liabilities	1.8
Fair Value, Inputs, Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	0
Short-term investments	0
Other current assets	0
Other non-current assets	46.5
Total	46.5
Other current liabilities	$ 0