|
Condensed Consolidating Financial Information (Narrative) (Details) (USD $)
|
3 Months Ended |
|---|---|
|
Mar. 31, 2013
|
|
| Holding company ownership in subsidiaries | 100.00% |
|
Comcast Holdings' ZONES due October 2029 [Member]
|
|
| Principal amount of debt securities subject to guarantee | 185,000,000 |
|
Comcast Holdings' ZONES due November 2029 [Member]
|
|
| Principal amount of debt securities not subject to guarantee | 62,000,000 |
|
Comcast And Comcast Cable Communications LLC [Member]
|
|
| Credit facility borrowing capacity | 6,250,000,000 |
|
NBCUniversal Enterprise [Member]
|
|
| Credit facility borrowing capacity | 1,350,000,000 |
| Principal amount of debt securities subject to guarantee | 4,000,000,000 |