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Significant Transaction (Universal Studios Japan) (Details) - USD ($) $ in Millions |  | 6 Months Ended
--- | --- | ---
Apr. 06, 2017 | Jun. 30, 2018 | Jun. 30, 2017
Business Acquisition [Line Items] |  |  |
Purchase of Universal Studios Japan noncontrolling interests |  | $ 0 | $ 2,299
NBCUniversal Media LLC [Member] |  |  |
Business Acquisition [Line Items] |  |  |
Purchase of Universal Studios Japan noncontrolling interests |  | $ 0 | $ 2,299
Universal Studios Japan [Member] |  |  |
Business Acquisition [Line Items] |  |  |
Purchase of Universal Studios Japan noncontrolling interests | $ 2,300 |  |
Universal Studios Japan [Member] | NBCUniversal Media LLC [Member] |  |  |
Business Acquisition [Line Items] |  |  |
Purchase of Universal Studios Japan noncontrolling interests | $ 2,300 |  |

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- Definition The cash outflow associated with the purchase of noncontrolling interest during the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3213-108585 + Details
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