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Supplemental Financial Information (Noncash Investing and Financing Activities)(Details) $ / shares in Units, $ in Millions | 6 Months Ended
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Jun. 30, 2018 USD ($) $ / shares
Supplemental Financial Information [Line Items] |
Property and equipment and intangible assets accrued but not yet paid | $ 2,100
Dividends payable | $ 871
Dividends payable (in dollars per share) | $ / shares | $ 0.19
NBCUniversal Media LLC [Member] |
Supplemental Financial Information [Line Items] |
Property and equipment and intangible assets accrued but not yet paid | $ 1,200
Universal Beijing Resort [Member] |
Supplemental Financial Information [Line Items] |
Assets contributed to variable interest entity | 391
Universal Beijing Resort [Member] | NBCUniversal Media LLC [Member] |
Supplemental Financial Information [Line Items] |
Assets contributed to variable interest entity | $ 391

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