Marketable Securities (Investments) (Details) (Preferred Stock [Member], USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments in equity securities	$ 22.7	$ 20.9

Equity securities categorized neither as held-to-maturity nor trading which are intended be sold within one year from the balance sheet date or the normal operating cycle, whichever is longer.

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

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-Name Accounting Research Bulletin (ARB)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

+ Details