Discontinued Operations (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from the Sale of Income-Producing Properties	$ 0	$ 22.4	$ 8.9	$ 36.6
Gain on Sale of Income-Producing Properties	0	8.7	3.9	15.3
Real Estate Leasing Operating Profit	0	9.3	3.9	16.7
Income Tax Expense	0	3.7	1.5	6.7
Income from Discontinued Operations	0	5.6	2.4	10.0
Real Estate Leasing [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Real Estate Leasing Revenue	0	0.9	0.1	2.1
Real Estate Leasing Operating Profit	$ 0	$ 0.6	$ 0	$ 1.4

Tax effect allocated to a disposal group that is classified as a component of the entity reported as a separate component of income before extraordinary items. Includes the tax effects of the following: income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

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-Name Statement of Financial Accounting Standard (FAS)

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Reference 5: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

- Definition

Amount of income (loss) from a disposal group, net of income tax, reported as a separate component of income before extraordinary items after deduction or consideration of the amount allocable to noncontrolling interests. Includes, net of tax, income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

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