Note 12. Stock-Based Compensation Introduction Narrative (Details) shares in Millions	12 Months Ended
Dec. 31, 2018 Performance_metrics Rate shares
Shares available for future grant under the plan (in shares)	5
Retirement Eligibility Age	65 years
Retirement Eligibility Age with Ten Years of Service	55 years
Retirement Eligibility Years Tenure	10 years
Retirement Eligibility Service Requirement	1 year
Maximum
Shares authorized for issuance under the plan (in shares)	6
Restricted Stock Units
Award Vesting Period	3 years
Annual Vesting Percentage \| Rate	33.33%
Performance Share Units
Award Vesting Period	3 years
Annual Vesting Percentage	33.33%
Number of performance metrics	2
The first performance metric \| Performance_metrics	1
Performance Share Units \| RTSR \| Minimum
Award Vesting Rights, Percentage	0.00%
Performance Share Units \| RTSR \| Maximum
Award Vesting Rights, Percentage	175.00%
Performance Share Units \| Cumulative Free Cash Flow \| Minimum
Award Vesting Rights, Percentage	0.00%
Performance Share Units \| Cumulative Free Cash Flow \| Maximum
Award Vesting Rights, Percentage	200.00%
Options
Award Vesting Period	4 years
Annual Vesting Percentage	25.00%
Award Expiration Period	10 years

Number of performance metrics

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- Definition

Age attained for which the retirement provision for equity grants provides for continued vesting of awards provided they have been employed or provided services to the Company for one year following the date of grant.

+ References

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Age attained for which the retirement provision for equity grants provides for continued vesting of awards if the employee has at least ten years of tenure with the Company and provided they have been employed or provided services to the Company for one year following the date of grant.

+ References

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Number of years of service required following the grant date or start of the performance period in order to qualify for the retirement provision for equity grants.

+ References

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Number of years of tenure with the Company required for employees aged 55 to qualify for the retirement provision for equity grants.

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Annual percentage of vesting of share-based compensation awards.

+ References

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- Definition

The first performance metric

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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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
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- Definition

The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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-Section 50
-Paragraph 2
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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.

+ References

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-Publisher FASB
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-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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- Definition

Percentage of vesting of share-based compensation awards.

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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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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