Sales and Division Results for Reportable Segments (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
Apr. 30, 2011
Segment Reporting Information [Line Items]
Increase in repositioning and restructuring reserve	$ 1

The increase (decrease) during the period in the carrying amount (including both current and noncurrent portions of the accrual) of the liability pertaining to the exit from or disposal of business activities or restructuring pursuant to a duly authorized plan, excluding costs or losses pertaining to an entity newly acquired in a business combination and to asset retirement obligations.

No definition available.

Name:	us-gaap_IncreaseDecreaseInRestructuringReserve
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration