Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]
Common stock, par value (usd per share)	$ 1	$ 1	$ 1
Common stock, shares outstanding	94,704,173us-gaap_CommonStockSharesOutstanding	100,129,380us-gaap_CommonStockSharesOutstanding	103,270,067us-gaap_CommonStockSharesOutstanding
Preferred stock, par value (usd per share)	$ 0us-gaap_PreferredStockNoParValue	$ 0us-gaap_PreferredStockNoParValue	$ 0us-gaap_PreferredStockNoParValue
Preferred stock, shares outstanding	0us-gaap_PreferredStockSharesOutstanding	40,406us-gaap_PreferredStockSharesOutstanding	101,086us-gaap_PreferredStockSharesOutstanding

Face amount or stated value per share of common stock.

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Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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Face amount per share of no-par value preferred stock nonredeemable or redeemable solely at the option of the issuer.

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Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased.

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