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Employment Benefit Plans Stock Compensation (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Share-based compensation expense [Abstract] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant | 2,096,292 |  |
Share Based Compensation Arrangement Shares Available for Future Issuance at Target | 3,058,603 |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification |  |  | $ 0
Share-based Payment Arrangement, Expense | $ 11 | $ 12 | 12
Total stock-based compensation (after-tax) | $ 11 | $ 12 | 12
Common stock, shares authorized | 130,000,000 | 130,000,000 |
2013 Plan |  |  |
Share-based compensation expense [Abstract] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | 4,000,000 |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | 4,000,000 |  |
2020 plan |  |  |
Share-based compensation expense [Abstract] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | 1,475,000 |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | 1,475,000 |  |
Share-based Payment Arrangement, Option [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Share-based Payment Arrangement, Expense | $ 0 | $ 0 | 0
Restricted Stock Units (RSUs) [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Share-based Payment Arrangement, Expense | 3 | 4 | 6
Performance Shares [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Share-based Payment Arrangement, Expense | 8 | 8 | 6
Retained Earnings [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Share-based Payment Arrangement, Expense | $ 0 | $ 0 | $ 0

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- Definition Amount of expense for award under share-based payment arrangement. Excludes amount capitalized. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5047-113901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 14.F) -URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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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 Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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