v2.4.0.6
Noncontrolling Interests (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended 6 Months Ended
Jun. 30, 2012
Jun. 30, 2011
Jun. 30, 2012
Jun. 30, 2011
GE ownership percentage in new company formed in connection with the NBC Universal transaction 49.00%   49.00%  
Net income attributable to Comcast Corporation $ 1,348 $ 1,022 $ 2,572 $ 1,965
Increase in Comcast Corporation additional paid-in capital resulting from the issuance of noncontrolling equity interest     0 1,692
Increase in Comcast Corporation additional paid-in capital resulting from the purchase of noncontrolling interest     2 0
Changes in equity resulting from net income attributable to Comcast Corporation and transfers from (to) noncontrolling interests     $ 2,574 $ 3,657