Stock-Based Compensation (Details Textual) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
Jun. 30, 2012 Plans	Jun. 30, 2011	Dec. 31, 2011
Stock Based Compensation (Textual) [Abstract]
Number of employee stock ownership plans	2
Common shares issued from exercise of stock option outstanding	0.7	2.6	4.4

Number of share options (or share units) exercised during the current period.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

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

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration