Stockholders' Equity (Reconciliation Of Denominators Used In Computation Of Basic And Diluted Earnings Per Share) (Details) - shares	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stockholders' Equity Note [Abstract]
Basic weighted average shares outstanding (in shares)	286,966,917	288,208,435	288,949,525
Weighted shares assumed upon exercise of stock options (in shares)	195,847	134,298	207,998
Diluted weighted average shares outstanding (in shares)	287,162,764	288,342,733	289,157,523

Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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