Guarantees (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
Jun. 30, 2011
Guarantees (Textuals) [Abstract]
Total number of guarantees	35
Maximum amount payable if required to perform under guarantees	29.2
Minimum Range [Member]
Guarantees (Textuals) [Abstract]
Range of remaining terms of guarantees	1
Maximum Range [Member]
Guarantees (Textuals) [Abstract]
Range of remaining terms of guarantees	96

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 45
-Paragraph 13
-Subparagraph b

Name:	us-gaap_GuaranteeObligationsMaximumExposure
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant