Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Statement of Financial Position [Abstract]
Common stock, par value (usd per share)	$ 1	$ 1	$ 1
Common stock, shares outstanding	93,186,295us-gaap_CommonStockSharesOutstanding	94,704,173us-gaap_CommonStockSharesOutstanding	99,651,879us-gaap_CommonStockSharesOutstanding
Preferred stock, par value (usd per share)
Preferred stock, shares outstanding	0us-gaap_PreferredStockSharesOutstanding	0us-gaap_PreferredStockSharesOutstanding	21,588us-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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