Amount remaining of a stock repurchase plan authorized.

No definition available.

Name:	us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Share Repurchases - Additional Information (Details) - USD ($) $ in Millions	Oct. 31, 2015	Feb. 26, 2015	Jan. 31, 2015	Nov. 01, 2014
Disclosure Share Repurchases Additional Information [Abstract]
Stock Repurchase Program, Authorized Amount		$ 2,500
Share repurchases, remaining amount	$ 495
Stock Repurchase Program Amount Not Paid	$ 0		$ 15	$ 0