Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ 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 |
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| QuarterlyFinancialInformationDisclosure [Abstract] | |||||||||||
| Revenue | $ 19,245 | $ 18,669 | $ 18,743 | $ 17,853 | $ 17,732 | $ 16,791 | $ 16,844 | $ 17,408 | $ 74,510 | $ 68,775 | $ 64,657 |
| Operating income | 4,002 | 4,001 | 4,105 | 3,890 | 3,787 | 3,745 | 3,804 | 3,568 | 15,998 | 14,904 | 13,563 |
| 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 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 |
| Dividends declared per common share | $ 0.25 | $ 0.25 | $ 0.25 | $ 0.25 | $ 0.225 | $ 0.225 | $ 0.225 | $ 0.225 | $ 1 | $ 0.9 | $ 0.78 |
| Change In Income Tax Expense Related To Effectively Settled Uncertain Tax Positions | $ 759 | ||||||||||
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- Definition Represents the change in income tax expense as a result of a reduction in the accrual for uncertain tax positions and related accrued interest on these tax positions, net of any indemnification. No definition available.
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- Definition Aggregate dividends declared during the period for each share of common stock outstanding. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The net result for the period of deducting operating expenses from operating revenues. No definition available.
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- References No definition available.
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- Definition Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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