Shareholders' Equity, Earnings Per Share And Stock-Based Compensation [Line Items]

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- Definition

Stock Repurchase Program, Total Number of Shares Repurchased To Date

+ References

No definition available.

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- Definition

Stock Repurchase Program, Total Shares Repurchased To Date, Amount

+ References

No definition available.

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- Definition

Aggregate dividends declared during the period for each share of common stock outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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- Definition

Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation.

+ References

No definition available.

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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

+ References

No definition available.

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Earnings Per Share, Stock-Based Compensation and Share Repurchase Plan (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 12, 2014
Shareholders' Equity, Earnings Per Share And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	1,501,578		1,181,805
Stock Repurchase Program, Number of Shares Authorized to be Repurchased				10,000,000
Stock Repurchase Program, Total Number of Shares Repurchased To Date	2,000,000
Stock Repurchase Program, Total Shares Repurchased To Date, Amount	$ 100
Restricted Stock Units (RSUs) [Member]
Shareholders' Equity, Earnings Per Share And Stock-Based Compensation [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Share-based Awards Other than Options	$ 19
Restricted Stock Units (RSUs) [Member] \| Minimum [Member]
Shareholders' Equity, Earnings Per Share And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	1 year
Restricted Stock Units (RSUs) [Member] \| Maximum [Member]
Shareholders' Equity, Earnings Per Share And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Dividend Declared [Member]
Shareholders' Equity, Earnings Per Share And Stock-Based Compensation [Line Items]
Common Stock, Dividends, Per Share, Declared	$ 0.15	$ 0.27