Investments (Details Textuals 8) (USD $) In Billions, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011
Leveraged Leases [Abstract]
Deferred income tax liability related to leveraged leases	$ 1.6	$ 1.5
Loans and Leases Receivable, Other Information	Rental receivables are generally due in periodic installments. The payment periods range from one to 15 years but, in certain circumstances can be over 30 years.
Percentage of rental receivables performing	100.00%	100.00%

Taxes arising from arrangements meeting the criteria for classification as leveraged leases due to timing differences between accounting and tax income recognition.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 30

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=7662751&loc=d3e45152-112736

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 30

-Section 35

-Paragraph 33

-URI http://asc.fasb.org/extlink&oid=7662473&loc=d3e43930-112732

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 13

-Paragraph 43

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant