Fair Value (Narrative) (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012
Transfers out of Level 2 to Level 1, Assets	$ 106

Amount of transfers of financial instruments classified in shareholders' equity measured on a recurring basis out of level 2 of the fair value hierarchy into level 1.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (bb)

-URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258

Name:	us-gaap_FairValueEquityLevel2ToLevel1TransfersAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant