Related Party Transactions - Condensed Consolidated Statement of Income (Details) - USD ($) $ in Millions |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2015 |
Sep. 30, 2015 |
Jun. 30, 2015 |
Mar. 31, 2015 |
Dec. 31, 2014 |
Sep. 30, 2014 |
Jun. 30, 2014 |
Mar. 31, 2014 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Revenue | $ 19,245 | $ 18,669 | $ 18,743 | $ 17,853 | $ 17,732 | $ 16,791 | $ 16,844 | $ 17,408 | $ 74,510 | $ 68,775 | $ 64,657 |
| NBCUniversal Media LLC [Member] | |||||||||||
| Revenue | 28,462 | 25,428 | 23,650 | ||||||||
| Transactions With Comcast And Consolidated Subsidiaries [Member] | NBCUniversal Media LLC [Member] | |||||||||||
| Revenue | 1,349 | 1,315 | 1,262 | ||||||||
| Operating costs and expenses | (246) | (162) | (190) | ||||||||
| Other income (expense) | $ (37) | $ (43) | $ 0 | ||||||||