v2.4.1.9

Consolidated Statement of Income (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue	$ 17,732,000,000us-gaap_Revenues	$ 16,791,000,000us-gaap_Revenues	$ 16,844,000,000us-gaap_Revenues	$ 17,408,000,000us-gaap_Revenues	$ 16,926,000,000us-gaap_Revenues	$ 16,151,000,000us-gaap_Revenues	$ 16,270,000,000us-gaap_Revenues	$ 15,310,000,000us-gaap_Revenues	$ 68,775,000,000us-gaap_Revenues	$ 64,657,000,000us-gaap_Revenues	$ 62,570,000,000us-gaap_Revenues
Costs and Expenses:
Programming and production									20,912,000,000cmcsa_ProgrammingAndProductionCosts	19,670,000,000cmcsa_ProgrammingAndProductionCosts	19,929,000,000cmcsa_ProgrammingAndProductionCosts
Other operating and administrative									19,862,000,000cmcsa_OtherOperatingAndAdministrative	18,584,000,000cmcsa_OtherOperatingAndAdministrative	17,833,000,000cmcsa_OtherOperatingAndAdministrative
Advertising, marketing and promotion									5,078,000,000us-gaap_MarketingAndAdvertisingExpense	4,969,000,000us-gaap_MarketingAndAdvertisingExpense	4,831,000,000us-gaap_MarketingAndAdvertisingExpense
Depreciation									6,337,000,000us-gaap_Depreciation	6,254,000,000us-gaap_Depreciation	6,150,000,000us-gaap_Depreciation
Amortization									1,682,000,000us-gaap_AmortizationOfIntangibleAssets	1,617,000,000us-gaap_AmortizationOfIntangibleAssets	1,648,000,000us-gaap_AmortizationOfIntangibleAssets
Total costs and expenses									53,871,000,000us-gaap_CostsAndExpenses	51,094,000,000us-gaap_CostsAndExpenses	50,391,000,000us-gaap_CostsAndExpenses
Operating income	3,787,000,000us-gaap_OperatingIncomeLoss	3,745,000,000us-gaap_OperatingIncomeLoss	3,804,000,000us-gaap_OperatingIncomeLoss	3,568,000,000us-gaap_OperatingIncomeLoss	3,647,000,000us-gaap_OperatingIncomeLoss	3,414,000,000us-gaap_OperatingIncomeLoss	3,435,000,000us-gaap_OperatingIncomeLoss	3,067,000,000us-gaap_OperatingIncomeLoss	14,904,000,000us-gaap_OperatingIncomeLoss	13,563,000,000us-gaap_OperatingIncomeLoss	12,179,000,000us-gaap_OperatingIncomeLoss
Other Income (Expense):
Interest expense									(2,617,000,000)us-gaap_InterestExpense	(2,574,000,000)us-gaap_InterestExpense	(2,521,000,000)us-gaap_InterestExpense
Investment income (loss), net									296,000,000us-gaap_InvestmentIncomeNonoperating	576,000,000us-gaap_InvestmentIncomeNonoperating	219,000,000us-gaap_InvestmentIncomeNonoperating
Equity in net income (losses) of investees, net									97,000,000us-gaap_IncomeLossFromEquityMethodInvestments	(86,000,000)us-gaap_IncomeLossFromEquityMethodInvestments	959,000,000us-gaap_IncomeLossFromEquityMethodInvestments
Other income (expense), net									(215,000,000)us-gaap_OtherNonoperatingIncomeExpense	(364,000,000)us-gaap_OtherNonoperatingIncomeExpense	773,000,000us-gaap_OtherNonoperatingIncomeExpense
Nonoperating income (expense)									(2,439,000,000)us-gaap_NonoperatingIncomeExpense	(2,448,000,000)us-gaap_NonoperatingIncomeExpense	(570,000,000)us-gaap_NonoperatingIncomeExpense
Income before income taxes									12,465,000,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	11,115,000,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	11,609,000,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest
Income tax expense									(3,873,000,000)us-gaap_IncomeTaxExpenseBenefit	(3,980,000,000)us-gaap_IncomeTaxExpenseBenefit	(3,744,000,000)us-gaap_IncomeTaxExpenseBenefit
Net income									8,592,000,000us-gaap_ProfitLoss	7,135,000,000us-gaap_ProfitLoss	7,865,000,000us-gaap_ProfitLoss
Net (income) loss attributable to noncontrolling interests and redeemable subsidiary preferred stock									(212,000,000)cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock	(319,000,000)cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock	(1,662,000,000)cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock
Net income attributable to Parent	1,925,000,000us-gaap_NetIncomeLoss	2,592,000,000us-gaap_NetIncomeLoss	1,992,000,000us-gaap_NetIncomeLoss	1,871,000,000us-gaap_NetIncomeLoss	1,913,000,000us-gaap_NetIncomeLoss	1,732,000,000us-gaap_NetIncomeLoss	1,734,000,000us-gaap_NetIncomeLoss	1,437,000,000us-gaap_NetIncomeLoss	8,380,000,000us-gaap_NetIncomeLoss	6,816,000,000us-gaap_NetIncomeLoss	6,203,000,000us-gaap_NetIncomeLoss
Basic earnings per common share attributable to Comcast Corporation shareholders	$ 0.75us-gaap_EarningsPerShareBasic	$ 1us-gaap_EarningsPerShareBasic	$ 0.77us-gaap_EarningsPerShareBasic	$ 0.72us-gaap_EarningsPerShareBasic	$ 0.73us-gaap_EarningsPerShareBasic	$ 0.66us-gaap_EarningsPerShareBasic	$ 0.66us-gaap_EarningsPerShareBasic	$ 0.55us-gaap_EarningsPerShareBasic	$ 3.24us-gaap_EarningsPerShareBasic	$ 2.6us-gaap_EarningsPerShareBasic	$ 2.32us-gaap_EarningsPerShareBasic
Diluted earnings per common share attributable to Comcast Corporation shareholders	$ 0.74us-gaap_EarningsPerShareDiluted	$ 0.99us-gaap_EarningsPerShareDiluted	$ 0.76us-gaap_EarningsPerShareDiluted	$ 0.71us-gaap_EarningsPerShareDiluted	$ 0.72us-gaap_EarningsPerShareDiluted	$ 0.65us-gaap_EarningsPerShareDiluted	$ 0.65us-gaap_EarningsPerShareDiluted	$ 0.54us-gaap_EarningsPerShareDiluted	$ 3.2us-gaap_EarningsPerShareDiluted	$ 2.56us-gaap_EarningsPerShareDiluted	$ 2.28us-gaap_EarningsPerShareDiluted
Dividends declared per common share	$ 0.225us-gaap_CommonStockDividendsPerShareDeclared	$ 0.225us-gaap_CommonStockDividendsPerShareDeclared	$ 0.225us-gaap_CommonStockDividendsPerShareDeclared	$ 0.225us-gaap_CommonStockDividendsPerShareDeclared	$ 0.195us-gaap_CommonStockDividendsPerShareDeclared	$ 0.195us-gaap_CommonStockDividendsPerShareDeclared	$ 0.195us-gaap_CommonStockDividendsPerShareDeclared	$ 0.195us-gaap_CommonStockDividendsPerShareDeclared	$ 0.9us-gaap_CommonStockDividendsPerShareDeclared	$ 0.78us-gaap_CommonStockDividendsPerShareDeclared	$ 0.65us-gaap_CommonStockDividendsPerShareDeclared
NBCUniversal Media, LLC [Member]
Revenue									25,428,000,000us-gaap_Revenues / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	23,650,000,000us-gaap_Revenues / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	23,812,000,000us-gaap_Revenues / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember
Costs and Expenses:
Programming and production									12,318,000,000cmcsa_ProgrammingAndProductionCosts / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	11,770,000,000cmcsa_ProgrammingAndProductionCosts / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	12,710,000,000cmcsa_ProgrammingAndProductionCosts / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember
Other operating and administrative									5,364,000,000cmcsa_OtherOperatingAndAdministrative / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	4,949,000,000cmcsa_OtherOperatingAndAdministrative / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	4,763,000,000cmcsa_OtherOperatingAndAdministrative / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember
Advertising, marketing and promotion									2,158,000,000us-gaap_MarketingAndAdvertisingExpense / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	2,199,000,000us-gaap_MarketingAndAdvertisingExpense / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	2,232,000,000us-gaap_MarketingAndAdvertisingExpense / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember
Depreciation									654,000,000us-gaap_Depreciation / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	639,000,000us-gaap_Depreciation / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	562,000,000us-gaap_Depreciation / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember
Amortization									841,000,000us-gaap_AmortizationOfIntangibleAssets / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	772,000,000us-gaap_AmortizationOfIntangibleAssets / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	764,000,000us-gaap_AmortizationOfIntangibleAssets / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember
Total costs and expenses									21,335,000,000us-gaap_CostsAndExpenses / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	20,329,000,000us-gaap_CostsAndExpenses / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	21,031,000,000us-gaap_CostsAndExpenses / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember
Operating income									4,093,000,000us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	3,321,000,000us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	2,781,000,000us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember
Other Income (Expense):
Interest expense									(508,000,000)us-gaap_InterestExpense / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	(515,000,000)us-gaap_InterestExpense / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	(480,000,000)us-gaap_InterestExpense / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember
Investment income (loss), net									27,000,000us-gaap_InvestmentIncomeNonoperating / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	17,000,000us-gaap_InvestmentIncomeNonoperating / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	27,000,000us-gaap_InvestmentIncomeNonoperating / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember
Equity in net income (losses) of investees, net									46,000,000us-gaap_IncomeLossFromEquityMethodInvestments / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	(93,000,000)us-gaap_IncomeLossFromEquityMethodInvestments / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	183,000,000us-gaap_IncomeLossFromEquityMethodInvestments / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember
Other income (expense), net									(218,000,000)us-gaap_OtherNonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	(402,000,000)us-gaap_OtherNonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	917,000,000us-gaap_OtherNonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember
Nonoperating income (expense)									(653,000,000)us-gaap_NonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	(993,000,000)us-gaap_NonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	647,000,000us-gaap_NonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember
Income before income taxes									3,440,000,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	2,328,000,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	3,428,000,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember
Income tax expense									(143,000,000)us-gaap_IncomeTaxExpenseBenefit / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	(206,000,000)us-gaap_IncomeTaxExpenseBenefit / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	(197,000,000)us-gaap_IncomeTaxExpenseBenefit / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember
Net income									3,297,000,000us-gaap_ProfitLoss / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	2,122,000,000us-gaap_ProfitLoss / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	3,231,000,000us-gaap_ProfitLoss / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember
Net income attributable to Parent									$ 3,115,000,000us-gaap_NetIncomeLoss / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	$ 1,968,000,000us-gaap_NetIncomeLoss / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember	$ 3,055,000,000us-gaap_NetIncomeLoss / dei_LegalEntityAxis = cmcsa_NBCUniversalMediaLLCMember

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