Long-term Debt (Debt Repayments) (Details) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2016 |
Mar. 31, 2015 |
|
| Repurchases and repayments of debt | $ 48 | $ 909 |
| NBCUniversal Media LLC [Member] | ||
| Repurchases and repayments of debt | 35 | $ 1 |
| Senior 2.875% Notes Due 2016 [Member] | ||
| Repurchases and repayments of debt | $ 1,000 | |
| Interest rate | 2.875% | |
| Maturity date | 2016 | |
| Senior 2.875% Notes Due 2016 [Member] | NBCUniversal Media LLC [Member] | ||
| Repurchases and repayments of debt | $ 1,000 | |
| Interest rate | 2.875% | |
| Maturity date | 2016 | |
| NBCUniversal Enterprise Senior Notes Due 2016 [Member] | ||
| Repurchases and repayments of debt | $ 700 | |
| Maturity date | 2016 | |