Financial Instruments Impaired Loans (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Fair Value Disclosures [Abstract]
Impaired loans without valuation allowances	$ 5.7	$ 5.8
Unpaid principal balance of impaired loans	$ 7.2	$ 7.3

Amount of unpaid principal balance of impaired financing receivables for which there is no related allowance for credit losses.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (a)(4)

-URI http://asc.fasb.org/extlink&oid=7512638&loc=d3e5212-111524

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