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Stock-based Compensation (Schedule Of Stock Option Exercises) (Details) - Stock Options [Member] - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Stock Option Aggregate Disclosures [Abstract] |  |  |
Intrinsic value of stock options exercised | $ 120 | $ 193 | $ 83
Cash received from option exercises | 95 | 130 | 76
Treasury shares repurchased for employee payroll taxes | (24) | (37) | (20)
Tax benefit realized from option exercises | 28 | 48 | 21
Aggregate grant-date fair value of stock options vested | $ 15 | $ 15 | $ 19

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- Definition Amount of tax benefit from exercise of option under share-based payment arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=120381028&loc=SL79508275-113901 + Details
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