Share Repurchases (Narrative) (Details) (USD $) In Billions, unless otherwise specified	0 Months Ended	3 Months Ended
Jun. 03, 2011 2011 Share Repurchase Program [Member]	Oct. 31, 2012 2012 Share Repurchase Program [Member]
Equity, Class of Treasury Stock [Line Items]
Share repurchase program, authorized amount	$ 15.0
Stock Repurchase Program, Remaining Authorized Repurchase Amount		$ 6.7

The remaining repurchase amount authorized by an entity's Board of Directors under a stock repurchase plan.

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration