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Income Taxes (Unrecognized Tax Benefits That Would/Not Reduce The Effective Tax Rate) (Details) - USD ($) $ in Millions | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
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Unrecognized Tax Benefits That Would Impact Effective Tax Rate [Abstract] |  |  |  |
Unrecognized tax benefits that would reduce the effective tax rate | $ 52 | $ 39 | $ 63 |
Unrecognized tax benefits that would not reduce the effective tax rate | 22 | 25 | 111 |
Total unrecognized tax benefits | $ 74 | $ 64 | $ 174 | $ 179

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- Definition Amount of unrecognized tax benefits. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 45 -Paragraph 10B -URI http://asc.fasb.org/extlink&oid=120406818&loc=SL37586934-109318 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319 + Details
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- Definition The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319 + Details
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