Shares issued under other than stock options plan counted in long-term incentive plan.

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- Definition

Shares issued under stock options plan counted in long-term incentive plan.

+ References

No definition available.

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- Definition

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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- Definition

Aggregate number of common shares reserved for future issuance.

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- Definition

Unrecognized cost of unvested share-based compensation awards.

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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- Definition

Amount of cash outflow to satisfy an employee's income tax withholding obligation as part of a net-share settlement of a share-based award.

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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.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Total number of shares issued during the period, including shares forfeited, as a result of Restricted Stock Awards.

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Aggregate value of stock related to Restricted Stock Awards issued during the period.

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Long-term Incentive Plans (Narrative) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Omnibus Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shareholder approved increase in common stock reserved and available for issuance	14,000,000
Shares issued under Omnibus Plan in connection with stock options, count	1
Shares/units available for future grants	2,471,234
Omnibus Plan [Member] \| After May 1, 2012 Amendment [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued under Omnibus Plan in connection with other than stock options, count	1.28
Omnibus Plan [Member] \| Prior To May 1, 2012 Amendment [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued under Omnibus Plan in connection with other than stock options, count	2
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, value, restricted stock award, gross	$ 37	$ 6
Share-based compensation expense (benefit)	6	10	$ 16
Tax charge related to share-based compensation	0	$ 0	1
Unrecognized compensation cost	$ 36
Expected to be recognized as expense over a weighted average period, years	3 years 3 months 18 days
Restricted Stock [Member] \| Stock Price Targets [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares granted	247,286	65,287
Restricted Stock [Member] \| Internal Performance Conditions [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares granted		127,001
Restricted Stock [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Long-term incentive awards vesting period, years	3 years
Restricted Stock [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Long-term incentive awards vesting period, years	7 years
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Tax charge related to share-based compensation	$ 0	$ 0	$ 1
Long-term incentive awards vesting period, years	5 years
Employee Stock Option [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Long-term incentive awards expiration period, years	7 years
Employee Stock Option [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Long-term incentive awards expiration period, years	10 years