v3.3.1.900
Earnings Per Share (Details) - USD ($)
$ / shares in Units, shares in Millions, $ 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
Earnings Per Share                      
Net income attributable to Parent $ 1,971 $ 1,996 $ 2,137 $ 2,059 $ 1,925 $ 2,592 $ 1,992 $ 1,871 $ 8,163 $ 8,380 $ 6,816
Basic shares attributable to Comcast Corporation shareholders                 2,486 2,583 2,625
Assumed exercise or issuance of shares relating to stock plans                 32 37 40
Diluted shares attributable to Comcast Corporation shareholders                 2,518 2,620 2,665
Basic earnings per common share attributable to Comcast Corporation shareholders $ 0.8 $ 0.81 $ 0.85 $ 0.82 $ 0.75 $ 1 $ 0.77 $ 0.72 $ 3.28 $ 3.24 $ 2.6
Diluted earnings per common share attributable to Comcast Corporation shareholders $ 0.79 $ 0.8 $ 0.84 $ 0.81 $ 0.74 $ 0.99 $ 0.76 $ 0.71 $ 3.24 $ 3.2 $ 2.56