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Other Income (Narrative) (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2018 | Dec. 31, 2017
Other Income [Abstract] |  |
Income (Loss) from Individually Significant Component Disposed of or Held-for-sale, Excluding Discontinued Operations, before Income Tax |  | $ 11
Gain on remeasurement of Tax Receivable Agreement liability | $ 3 | $ 93

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- Definition Gain on Remeasurement of Tax Receivable Agreement liability as result of the reduction in the U.S. corporate tax rate to 21% + References No definition available. + Details
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- Definition Amount before tax of income (loss) from an individually significant component disposed of or held-for-sale including the portion attributable to the noncontrolling interest. Excludes discontinued operations. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 3A -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=109226691&loc=SL51724579-110230 + Details
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- References No definition available. + Details
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