Discontinued Operations (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of income-producing properties	$ 1.9us-gaap_GainLossOnDispositionOfAssets	$ 0us-gaap_GainLossOnDispositionOfAssets
Income from discontinued operations	0	34.3
Held-for-sale or Disposed of by Sale, Not Discontinued Operations \| Retail Site
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of real estate property sold	46,500
Discontinued Operations \| Real Estate Leasing
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from the sale of income-producing properties	0	70.1
Real estate leasing revenue	0	0.3
Revenue from discontinued operations	0	70.4
Gain on sale of income-producing properties	0	55.9
Real estate leasing operating profit	0	0.3
Total operating profit before taxes	0	56.2
Income tax expense	0	21.9
Income from discontinued operations	$ 0	$ 34.3

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The cash inflow from the sale of productive assets related to a discontinued operations.

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Overall income (loss) from a disposal group that is classified as a component of the entity, before income tax, reported as a separate component of income before extraordinary items. Includes the following (before income 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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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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Amount of operating income or loss attributable to the disposal group, including a component of the entity (discontinued operation), during the reporting period.

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Amount of rental income attributable to the disposal group, including a component of the entity (discontinued operation).

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Amount of sales or other form of revenues attributable to the disposal group, including a component of the entity (discontinued operation), during the reporting period.

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Amount of gain (loss) on sale or disposal of property, plant and equipment assets, excluding oil and gas property and timber property.

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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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