Notional Amounts for All Outstanding Derivatives and Weighted-Average Exchange Rates of Foreign Exchange Forward Contracts (Detail) (Derivatives Designated as Non-Hedging Instruments, Forward foreign exchange contracts, USD $) In Millions, unless otherwise specified	Jan. 31, 2015
Inventories | Currency, British Pound Sterling
Derivative [Line Items]
Notional value of contracts outstanding	$ 63
Weighted-Average Exchange Rate	0.7996
Intercompany | Currency, British Pound Sterling
Derivative [Line Items]
Notional value of contracts outstanding	32
Weighted-Average Exchange Rate	0.7640
Intercompany | Currency, Canadian Dollar
Derivative [Line Items]
Notional value of contracts outstanding	$ 2
Weighted-Average Exchange Rate	1.1912