Consolidated Balance Sheets Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.10	$ 0.10
Preferred stock issued (in shares)	5,000,000	5,000,000
Preferred stock outstanding (in shares)	0	0
Common stock, par value (in dollar per share)	$ 0.2	$ 0.2
Common shares authorized (in shares)	500,000,000	500,000,000
Common shares issued (in shares)	183,024,006	182,993,640
Common shares outstanding (in shares)	183,024,006	182,993,640
Treasury stock issued at cost (in shares)	169,652,871	169,683,237

Face amount or stated value per share of common stock.

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The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
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-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
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Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.

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Total number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) issued to shareholders (includes related preferred shares that were issued, repurchased, and remain in the treasury). May be all or portion of the number of preferred shares authorized. Excludes preferred shares that are classified as debt.

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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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No definition available.

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- Definition

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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-Name Accounting Standards Codification
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-Section 45
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-URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655

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