Stock-Based Incentive Compensation Plans (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Performance Shares [Member] \| Maximum [Member]
Narrative [Abstract]
Share based compensation, Performance issuance as percent or original grant	200.00%
Performance Shares [Member] \| Minimum [Member]
Narrative [Abstract]
Share based compensation, Performance issuance as percent or original grant	0.00%
Stock options with performance conditions [Member]
Narrative [Abstract]
Contractual term	5 years
Vesting period (in years)	2 years
Total fair value of options vested	$ 1	$ 2	$ 1
Total intrinsic value of options exercised	$ 2	12	3
Stock options with service conditions [Member]
Narrative [Abstract]
Contractual term	10 years
Vesting period (in years)	3 years
Total fair value of options vested	$ 6	6	6
Total intrinsic value of options exercised	$ 11	23	22
Non-employee Stock Appreciation Rights [Member]
Narrative [Abstract]
Contractual term	5 years
Vesting period (in years)	4 years
Percentage of SARs vesting each year over four-year period	25.00%
SARs liability	$ 1	3
Payment for SARs exercised	$ 1	$ 3	$ 2

n/a

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Percentage of vesting of share-based compensation awards.

+ References

No definition available.

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The total fair value of share-based awards for which the grantee gained the right during the reporting period, by satisfying service or performance requirements, to receive or retain shares, options, or cash in accordance with the terms of the arrangement.

+ References

No definition available.

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Share based compensation, Performance issuance as percent or original grant

+ References

No definition available.

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- Definition

Aggregate carrying value as of the balance sheet date of the liabilities for stock option plans and other equity-based compensation arrangements.

+ References

No definition available.

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- Definition

Aggregate cash paid by the entity during the period to settle equity instruments granted under equity-based payment arrangements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (k)
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Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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-Publisher FASB
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-Topic 718
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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

+ References

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-Publisher FASB
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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.

+ References

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