0001166691 2021-07-29 2021-07-29 0001166691 us-gaap:CommonClassAMember 2021-07-29 2021-07-29 0001166691 cmcsa:Notes0.250percentDue2027Member 2021-07-29 2021-07-29 0001166691 cmcsa:Notes1.500percentDue2029Member 2021-07-29 2021-07-29 0001166691 cmcsa:Notes0.750percentdue2032Member 2021-07-29 2021-07-29 0001166691 cmcsa:Notes1.875percentdue2036Member 2021-07-29 2021-07-29 0001166691 cmcsa:Notes1.250percentdue2040Member 2021-07-29 2021-07-29 0001166691 cmcsa:GuaranteedNotes9.455PercentDue2022Member 2021-07-29 2021-07-29 0001166691 cmcsa:Notes5.50PercentDue2029Member 2021-07-29 2021-07-29 0001166691 cmcsa:ExchangeableSubordinatedDebentures2.0PercentDue2029Member 2021-07-29 2021-07-29 false 0001166691 8-K 2021-07-29 Comcast Corporation PA 001-32871 27-0000798 One Comcast Center Philadelphia, PA 19103-2838 215 286-1700 false false false false Class A Common Stock, $0.01 par value CMCSA NASDAQ 0.250% Notes due 2027 CMCS27 NASDAQ 1.500% Notes due 2029 CMCS29 NASDAQ 0.750% Notes due 2032 CMCS32 NASDAQ 1.875% Notes due 2036 CMCS36 NASDAQ 1.250% Notes due 2040 CMCS40 NASDAQ 9.455% Guaranteed Notes due 2022 CMCSA/22 NYSE 5.50% Notes due 2029 CCGBP29 NYSE 2.0% Exchangeable Subordinated Debentures due 2029 CCZ NYSE false