v3.3.1.900

Significant Transactions (Pro Forma Information) (Details) - Universal Studios Japan [Member] - USD ($) $ / shares in Units, $ in Millions | 12 Months Ended
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Dec. 31, 2015 | Dec. 31, 2014
Revenue [Pro Forma] | $ 75,563 | $ 69,860
Net Income [Pro Forma] | 8,640 | 8,758
Net income attributable to Comcast Corporation [Pro Forma] | $ 8,278 | $ 8,463
Basic earnings per common share attributable to Comcast Corporation shareholders [Pro Forma] | $ 3.33 | $ 3.28
Diluted earnings per common share attributable to Comcast Corporation shareholders [Pro Forma] | $ 3.29 | $ 3.23
NBC Universal Media LLC [Member] |  |
Revenue [Pro Forma] | $ 29,514 | $ 26,513
Net Income [Pro Forma] | 3,851 | 3,463
Net income attributable to Comcast Corporation [Pro Forma] | $ 3,529 | $ 3,198

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