Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Operating Assets and Facilities ($0 and $123.3 related to a consolidated VIE)	$ 8,545.4	$ 8,204.0
Less: allowance for depreciation ($0 and $39.7 related to a consolidated VIE)	(2,633.4)	(2,505.6)
Nonrecourse ($0 and $6.9 related to a consolidated VIE)	$ 0.0	$ 6.9
Common stock, par value	$ 0.625	$ 0.625
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares issued	66,891,983	66,776,290
Common stock, shares outstanding	39,880,034	41,970,098
Treasury stock, shares outstanding	27,011,949	24,806,192
Variable Interest Entity, Primary Beneficiary [Member]
Operating Assets and Facilities ($0 and $123.3 related to a consolidated VIE)	$ 0.0	$ 122.9
Less: allowance for depreciation ($0 and $39.7 related to a consolidated VIE)	0.0	(39.7)
Nonrecourse ($0 and $6.9 related to a consolidated VIE)	$ 0.0	$ 6.9

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Face amount or stated value per share of common stock.

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Number of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends.

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