Financial Instruments and Fair Value Measurements - Contractual Maturities of Debt Investments (Detail) (USD $) In Millions, unless otherwise specified	Oct. 24, 2014
Schedule of Available-for-sale Securities [Line Items]
Due in one year or less, Amortized Cost	$ 1,615.2
Due in two through five years, Amortized Cost	965.4
Due after ten years, Amortized Cost	23.3	[1]
Total, Amortized Cost	2,603.9
Due in one year or less, Estimated Fair Value	1,618.1
Due in two through five years, Estimated Fair Value	971.0
Due after ten years, Estimated Fair Value	23.0	[1]
Total, Estimated Fair Value	$ 2,612.1

[1] Consists of auction rate securities (ARSs) which have contractual maturities of greater than 10 years.