Securities (Summary Of Assumptions Utilized In Valuation Of Other-Than-Temporarily Impaired Residential Mortgage-Backed Securities Issued By Nongovernment-Sponsored Entities) (Details)	6 Months Ended
Jun. 30, 2012
Weighted Average [Member]
Constant voluntary prepayment rates	8.40%
Constant default rates	5.30%
Loss severities	47.40%
Minimum [Member]
Constant voluntary prepayment rates	1.60%
Constant default rates	4.20%
Loss severities	40.00%
Maximum [Member]
Constant voluntary prepayment rates	11.10%
Constant default rates	7.90%
Loss severities	52.00%

This item represents the default rate of the underlying assets in the security that was considered as one of the potential factors in reaching a conclusion that the available-for-sale investments are other than temporarily impaired and the amount of such impairment determined to be related to credit loss recognized in earnings.

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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 18A

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration