Stock-Based Compensation (Components Of Stock Options) (Details) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
Dec. 31, 2018 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at beginning of period, Options (in shares) \| shares	1.9
Granted, options (in shares) \| shares	0.0
Exercised, Options (in shares) \| shares	(0.3)
Outstanding at end of period, Options (in shares) \| shares	1.6
Vested or expected to vest (in shares) \| shares	1.6
Exercisable (vested) at end of period (in shares) \| shares	1.5
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding at the beginning of period, Weighted Average Exercise Price per Share (in dollars per share) \| $ / shares	$ 24.08
Granted, Weighted Average Exercise Price per Share (in dollars per share) \| $ / shares	0.00
Exercised, Weighted Average Exercise Price per Share (in dollars per share) \| $ / shares	17.92
Outstanding at end of period, Weighted Average Exercise Price per Share (in dollars per share) \| $ / shares	25.43
Vested or expected to vest (in dollars per share) \| $ / shares	25.43
Exercisable (vested) at 12/31/2018 (in dollars per share) \| $ / shares	$ 25.12
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Outstanding at end of period, Weighted Average Remaining Contractual Life in Years	2 years 10 months 16 days
Vested or expected to vest at end of period, Weighted Average Remaining Contractual Life in Years	2 years 10 months 16 days
Exercisable (vested) at end of period, Weighted Average Remaining Contractual Life in Years	2 years 9 months 16 days
Outstanding at end of period, Aggregate Intrinsic Value \| $	$ 17.8
Vested or expected to vest at end of period, Aggregate Intrinsic Value \| $	17.8
Exercisable (vested) at end of period, Aggregate Intrinsic Value \| $	$ 17.8

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- Definition

The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Gross number of share options (or share units) granted during the period.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Number of options outstanding, including both vested and non-vested options.

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Number of fully vested and expected to vest exercisable options that may be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Number of fully vested and expected to vest options outstanding that can be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted-average exercise price, at which grantee can acquire shares reserved for issuance, for fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for fully vested and expected to vest exercisable or convertible options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Number of share options (or share units) exercised during the current period.

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