v2.4.1.9

Condensed Consolidating Financial Information (Condensed Consolidating Statement of Income) (Details) (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
Service revenue |  |  |  |  |  |  |  |  | $ 68,775,000,000 us-gaap_SalesRevenueServicesNet | $ 64,657,000,000 us-gaap_SalesRevenueServicesNet | $ 62,570,000,000 us-gaap_SalesRevenueServicesNet
Revenue | 17,732,000,000 us-gaap_Revenues | 16,791,000,000 us-gaap_Revenues | 16,844,000,000 us-gaap_Revenues | 17,408,000,000 us-gaap_Revenues | 16,926,000,000 us-gaap_Revenues | 16,151,000,000 us-gaap_Revenues | 16,270,000,000 us-gaap_Revenues | 15,310,000,000 us-gaap_Revenues | 68,775,000,000 us-gaap_Revenues | 64,657,000,000 us-gaap_Revenues | 62,570,000,000 us-gaap_Revenues
Programming and production |  |  |  |  |  |  |  |  | 20,912,000,000 cmcsa_ProgrammingAndProductionCosts | 19,670,000,000 cmcsa_ProgrammingAndProductionCosts | 19,929,000,000 cmcsa_ProgrammingAndProductionCosts
Other operating and administrative |  |  |  |  |  |  |  |  | 19,862,000,000 cmcsa_OtherOperatingAndAdministrative | 18,584,000,000 cmcsa_OtherOperatingAndAdministrative | 17,833,000,000 cmcsa_OtherOperatingAndAdministrative
Advertising, marketing and promotion |  |  |  |  |  |  |  |  | 5,078,000,000 us-gaap_MarketingAndAdvertisingExpense | 4,969,000,000 us-gaap_MarketingAndAdvertisingExpense | 4,831,000,000 us-gaap_MarketingAndAdvertisingExpense
Depreciation |  |  |  |  |  |  |  |  | 6,337,000,000 us-gaap_Depreciation | 6,254,000,000 us-gaap_Depreciation | 6,150,000,000 us-gaap_Depreciation
Amortization |  |  |  |  |  |  |  |  | 1,682,000,000 us-gaap_AmortizationOfIntangibleAssets | 1,617,000,000 us-gaap_AmortizationOfIntangibleAssets | 1,648,000,000 us-gaap_AmortizationOfIntangibleAssets
Costs and expenses, total |  |  |  |  |  |  |  |  | 53,871,000,000 us-gaap_CostsAndExpenses | 51,094,000,000 us-gaap_CostsAndExpenses | 50,391,000,000 us-gaap_CostsAndExpenses
Operating income (loss) | 3,787,000,000 us-gaap_OperatingIncomeLoss | 3,745,000,000 us-gaap_OperatingIncomeLoss | 3,804,000,000 us-gaap_OperatingIncomeLoss | 3,568,000,000 us-gaap_OperatingIncomeLoss | 3,647,000,000 us-gaap_OperatingIncomeLoss | 3,414,000,000 us-gaap_OperatingIncomeLoss | 3,435,000,000 us-gaap_OperatingIncomeLoss | 3,067,000,000 us-gaap_OperatingIncomeLoss | 14,904,000,000 us-gaap_OperatingIncomeLoss | 13,563,000,000 us-gaap_OperatingIncomeLoss | 12,179,000,000 us-gaap_OperatingIncomeLoss
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 |  |  |  |  |  |  |  |  | 296,000,000 us-gaap_InvestmentIncomeNonoperating | 576,000,000 us-gaap_InvestmentIncomeNonoperating | 219,000,000 us-gaap_InvestmentIncomeNonoperating
Equity in net income (losses) of investees, net |  |  |  |  |  |  |  |  | 97,000,000 us-gaap_IncomeLossFromEquityMethodInvestments | (86,000,000)us-gaap_IncomeLossFromEquityMethodInvestments | 959,000,000 us-gaap_IncomeLossFromEquityMethodInvestments
Other income (expense), net |  |  |  |  |  |  |  |  | (215,000,000)us-gaap_OtherNonoperatingIncomeExpense | (364,000,000)us-gaap_OtherNonoperatingIncomeExpense | 773,000,000 us-gaap_OtherNonoperatingIncomeExpense
Nonoperating income (Expense), Total |  |  |  |  |  |  |  |  | (2,439,000,000)us-gaap_NonoperatingIncomeExpense | (2,448,000,000)us-gaap_NonoperatingIncomeExpense | (570,000,000)us-gaap_NonoperatingIncomeExpense
Income (loss) before income taxes |  |  |  |  |  |  |  |  | 12,465,000,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest | 11,115,000,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest | 11,609,000,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest
Income tax (expense) benefit |  |  |  |  |  |  |  |  | (3,873,000,000)us-gaap_IncomeTaxExpenseBenefit | (3,980,000,000)us-gaap_IncomeTaxExpenseBenefit | (3,744,000,000)us-gaap_IncomeTaxExpenseBenefit
Net income (loss) |  |  |  |  |  |  |  |  | 8,592,000,000 us-gaap_ProfitLoss | 7,135,000,000 us-gaap_ProfitLoss | 7,865,000,000 us-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 (loss) attributable to Parent | 1,925,000,000 us-gaap_NetIncomeLoss | 2,592,000,000 us-gaap_NetIncomeLoss | 1,992,000,000 us-gaap_NetIncomeLoss | 1,871,000,000 us-gaap_NetIncomeLoss | 1,913,000,000 us-gaap_NetIncomeLoss | 1,732,000,000 us-gaap_NetIncomeLoss | 1,734,000,000 us-gaap_NetIncomeLoss | 1,437,000,000 us-gaap_NetIncomeLoss | 8,380,000,000 us-gaap_NetIncomeLoss | 6,816,000,000 us-gaap_NetIncomeLoss | 6,203,000,000 us-gaap_NetIncomeLoss
Comprehensive income attributable to Parent |  |  |  |  |  |  |  |  | 8,178,000,000 us-gaap_ComprehensiveIncomeNetOfTax | 6,883,000,000 us-gaap_ComprehensiveIncomeNetOfTax | 6,370,000,000 us-gaap_ComprehensiveIncomeNetOfTax
Elimination and Consolidation Adjustments [Member] |  |  |  |  |  |  |  |  |  |  |
Service revenue |  |  |  |  |  |  |  |  | 0 us-gaap_SalesRevenueServicesNet / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | 0 us-gaap_SalesRevenueServicesNet / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | 0 us-gaap_SalesRevenueServicesNet / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember
Management fee revenue |  |  |  |  |  |  |  |  | (2,450,000,000)us-gaap_ManagementFeesRevenue / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | (2,319,000,000)us-gaap_ManagementFeesRevenue / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | (2,191,000,000)us-gaap_ManagementFeesRevenue / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember
Revenue |  |  |  |  |  |  |  |  | (2,450,000,000)us-gaap_Revenues / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | (2,319,000,000)us-gaap_Revenues / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | (2,191,000,000)us-gaap_Revenues / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember
Programming and production |  |  |  |  |  |  |  |  | 0 cmcsa_ProgrammingAndProductionCosts / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | 0 cmcsa_ProgrammingAndProductionCosts / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | 0 cmcsa_ProgrammingAndProductionCosts / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember
Other operating and administrative |  |  |  |  |  |  |  |  | (2,450,000,000)cmcsa_OtherOperatingAndAdministrative / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | (2,319,000,000)cmcsa_OtherOperatingAndAdministrative / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | (2,191,000,000)cmcsa_OtherOperatingAndAdministrative / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember
Advertising, marketing and promotion |  |  |  |  |  |  |  |  | 0 us-gaap_MarketingAndAdvertisingExpense / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | 0 us-gaap_MarketingAndAdvertisingExpense / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | 0 us-gaap_MarketingAndAdvertisingExpense / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember
Depreciation |  |  |  |  |  |  |  |  | 0 us-gaap_Depreciation / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | 0 us-gaap_Depreciation / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | 0 us-gaap_Depreciation / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember
Amortization |  |  |  |  |  |  |  |  | 0 us-gaap_AmortizationOfIntangibleAssets / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | 0 us-gaap_AmortizationOfIntangibleAssets / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | 0 us-gaap_AmortizationOfIntangibleAssets / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember
Costs and expenses, total |  |  |  |  |  |  |  |  | (2,450,000,000)us-gaap_CostsAndExpenses / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | (2,319,000,000)us-gaap_CostsAndExpenses / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | (2,191,000,000)us-gaap_CostsAndExpenses / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember
Operating income (loss) |  |  |  |  |  |  |  |  | 0 us-gaap_OperatingIncomeLoss / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | 0 us-gaap_OperatingIncomeLoss / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | 0 us-gaap_OperatingIncomeLoss / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember
Interest expense |  |  |  |  |  |  |  |  | 0 us-gaap_InterestExpense / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | 0 us-gaap_InterestExpense / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | 0 us-gaap_InterestExpense / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember
Investment income (loss), net |  |  |  |  |  |  |  |  | 0 us-gaap_InvestmentIncomeNonoperating / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | 0 us-gaap_InvestmentIncomeNonoperating / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | 0 us-gaap_InvestmentIncomeNonoperating / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember
Equity in net income (losses) of investees, net |  |  |  |  |  |  |  |  | (40,417,000,000)us-gaap_IncomeLossFromEquityMethodInvestments / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | (33,251,000,000)us-gaap_IncomeLossFromEquityMethodInvestments / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | (32,425,000,000)us-gaap_IncomeLossFromEquityMethodInvestments / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember
Other income (expense), net |  |  |  |  |  |  |  |  | 0 us-gaap_OtherNonoperatingIncomeExpense / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | 0 us-gaap_OtherNonoperatingIncomeExpense / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | 0 us-gaap_OtherNonoperatingIncomeExpense / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember
Nonoperating income (Expense), Total |  |  |  |  |  |  |  |  | (40,417,000,000)us-gaap_NonoperatingIncomeExpense / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | (33,251,000,000)us-gaap_NonoperatingIncomeExpense / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | (32,425,000,000)us-gaap_NonoperatingIncomeExpense / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember
Income (loss) before income taxes |  |  |  |  |  |  |  |  | (40,417,000,000)us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | (33,251,000,000)us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | (32,425,000,000)us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember
Income tax (expense) benefit |  |  |  |  |  |  |  |  | 0 us-gaap_IncomeTaxExpenseBenefit / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | 0 us-gaap_IncomeTaxExpenseBenefit / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | 0 us-gaap_IncomeTaxExpenseBenefit / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember
Net income (loss) |  |  |  |  |  |  |  |  | (40,417,000,000)us-gaap_ProfitLoss / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | (33,251,000,000)us-gaap_ProfitLoss / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | (32,425,000,000)us-gaap_ProfitLoss / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember
Net (income) loss attributable to noncontrolling interests and redeemable subsidiary preferred stock |  |  |  |  |  |  |  |  | 0 cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | 0 cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | 0 cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember
Net income (loss) attributable to Parent |  |  |  |  |  |  |  |  | (40,417,000,000)us-gaap_NetIncomeLoss / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | (33,251,000,000)us-gaap_NetIncomeLoss / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | (32,425,000,000)us-gaap_NetIncomeLoss / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember
Comprehensive income attributable to Parent |  |  |  |  |  |  |  |  | (40,178,000,000)us-gaap_ComprehensiveIncomeNetOfTax / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | (33,175,000,000)us-gaap_ComprehensiveIncomeNetOfTax / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember | (32,575,000,000)us-gaap_ComprehensiveIncomeNetOfTax / us-gaap_ConsolidationItemsAxis = cmcsa_EliminationAndConsolidationAdjustmentsMember
Comcast Parent [Member] |  |  |  |  |  |  |  |  |  |  |
Service revenue |  |  |  |  |  |  |  |  | 0 us-gaap_SalesRevenueServicesNet / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 0 us-gaap_SalesRevenueServicesNet / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 0 us-gaap_SalesRevenueServicesNet / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Management fee revenue |  |  |  |  |  |  |  |  | 947,000,000 us-gaap_ManagementFeesRevenue / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 897,000,000 us-gaap_ManagementFeesRevenue / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 848,000,000 us-gaap_ManagementFeesRevenue / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Revenue |  |  |  |  |  |  |  |  | 947,000,000 us-gaap_Revenues / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 897,000,000 us-gaap_Revenues / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 848,000,000 us-gaap_Revenues / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Programming and production |  |  |  |  |  |  |  |  | 0 cmcsa_ProgrammingAndProductionCosts / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 0 cmcsa_ProgrammingAndProductionCosts / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 0 cmcsa_ProgrammingAndProductionCosts / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Other operating and administrative |  |  |  |  |  |  |  |  | 751,000,000 cmcsa_OtherOperatingAndAdministrative / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 403,000,000 cmcsa_OtherOperatingAndAdministrative / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 401,000,000 cmcsa_OtherOperatingAndAdministrative / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Advertising, marketing and promotion |  |  |  |  |  |  |  |  | 0 us-gaap_MarketingAndAdvertisingExpense / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 0 us-gaap_MarketingAndAdvertisingExpense / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 0 us-gaap_MarketingAndAdvertisingExpense / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Depreciation |  |  |  |  |  |  |  |  | 34,000,000 us-gaap_Depreciation / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 30,000,000 us-gaap_Depreciation / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 30,000,000 us-gaap_Depreciation / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Amortization |  |  |  |  |  |  |  |  | 6,000,000 us-gaap_AmortizationOfIntangibleAssets / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 5,000,000 us-gaap_AmortizationOfIntangibleAssets / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 4,000,000 us-gaap_AmortizationOfIntangibleAssets / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Costs and expenses, total |  |  |  |  |  |  |  |  | 791,000,000 us-gaap_CostsAndExpenses / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 438,000,000 us-gaap_CostsAndExpenses / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 435,000,000 us-gaap_CostsAndExpenses / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Operating income (loss) |  |  |  |  |  |  |  |  | 156,000,000 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 459,000,000 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 413,000,000 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Interest expense |  |  |  |  |  |  |  |  | (1,621,000,000)us-gaap_InterestExpense / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | (1,523,000,000)us-gaap_InterestExpense / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | (1,430,000,000)us-gaap_InterestExpense / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Investment income (loss), net |  |  |  |  |  |  |  |  | 3,000,000 us-gaap_InvestmentIncomeNonoperating / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 0 us-gaap_InvestmentIncomeNonoperating / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 8,000,000 us-gaap_InvestmentIncomeNonoperating / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Equity in net income (losses) of investees, net |  |  |  |  |  |  |  |  | 9,330,000,000 us-gaap_IncomeLossFromEquityMethodInvestments / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 7,509,000,000 us-gaap_IncomeLossFromEquityMethodInvestments / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 6,858,000,000 us-gaap_IncomeLossFromEquityMethodInvestments / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Other income (expense), net |  |  |  |  |  |  |  |  | 0 us-gaap_OtherNonoperatingIncomeExpense / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | (2,000,000)us-gaap_OtherNonoperatingIncomeExpense / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 2,000,000 us-gaap_OtherNonoperatingIncomeExpense / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Nonoperating income (Expense), Total |  |  |  |  |  |  |  |  | 7,712,000,000 us-gaap_NonoperatingIncomeExpense / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 5,984,000,000 us-gaap_NonoperatingIncomeExpense / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 5,438,000,000 us-gaap_NonoperatingIncomeExpense / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Income (loss) before income taxes |  |  |  |  |  |  |  |  | 7,868,000,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 6,443,000,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 5,851,000,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Income tax (expense) benefit |  |  |  |  |  |  |  |  | 512,000,000 us-gaap_IncomeTaxExpenseBenefit / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 373,000,000 us-gaap_IncomeTaxExpenseBenefit / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 352,000,000 us-gaap_IncomeTaxExpenseBenefit / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Net income (loss) |  |  |  |  |  |  |  |  | 8,380,000,000 us-gaap_ProfitLoss / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 6,816,000,000 us-gaap_ProfitLoss / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 6,203,000,000 us-gaap_ProfitLoss / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Net (income) loss attributable to noncontrolling interests and redeemable subsidiary preferred stock |  |  |  |  |  |  |  |  | 0 cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 0 cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 0 cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Net income (loss) attributable to Parent |  |  |  |  |  |  |  |  | 8,380,000,000 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 6,816,000,000 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 6,203,000,000 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Comprehensive income attributable to Parent |  |  |  |  |  |  |  |  | 8,178,000,000 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 6,883,000,000 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | 6,370,000,000 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Comcast Holdings [Member] |  |  |  |  |  |  |  |  |  |  |
Service revenue |  |  |  |  |  |  |  |  | 0 us-gaap_SalesRevenueServicesNet / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 us-gaap_SalesRevenueServicesNet / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 us-gaap_SalesRevenueServicesNet / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember
Management fee revenue |  |  |  |  |  |  |  |  | 0 us-gaap_ManagementFeesRevenue / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 us-gaap_ManagementFeesRevenue / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 us-gaap_ManagementFeesRevenue / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember
Revenue |  |  |  |  |  |  |  |  | 0 us-gaap_Revenues / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 us-gaap_Revenues / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 us-gaap_Revenues / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember
Programming and production |  |  |  |  |  |  |  |  | 0 cmcsa_ProgrammingAndProductionCosts / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 cmcsa_ProgrammingAndProductionCosts / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 cmcsa_ProgrammingAndProductionCosts / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember
Other operating and administrative |  |  |  |  |  |  |  |  | 0 cmcsa_OtherOperatingAndAdministrative / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 cmcsa_OtherOperatingAndAdministrative / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 cmcsa_OtherOperatingAndAdministrative / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember
Advertising, marketing and promotion |  |  |  |  |  |  |  |  | 0 us-gaap_MarketingAndAdvertisingExpense / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 us-gaap_MarketingAndAdvertisingExpense / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 us-gaap_MarketingAndAdvertisingExpense / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember
Depreciation |  |  |  |  |  |  |  |  | 0 us-gaap_Depreciation / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 us-gaap_Depreciation / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 us-gaap_Depreciation / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember
Amortization |  |  |  |  |  |  |  |  | 0 us-gaap_AmortizationOfIntangibleAssets / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 us-gaap_AmortizationOfIntangibleAssets / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 us-gaap_AmortizationOfIntangibleAssets / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember
Costs and expenses, total |  |  |  |  |  |  |  |  | 0 us-gaap_CostsAndExpenses / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 us-gaap_CostsAndExpenses / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 us-gaap_CostsAndExpenses / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember
Operating income (loss) |  |  |  |  |  |  |  |  | 0 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember
Interest expense |  |  |  |  |  |  |  |  | (11,000,000)us-gaap_InterestExpense / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | (11,000,000)us-gaap_InterestExpense / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | (23,000,000)us-gaap_InterestExpense / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember
Investment income (loss), net |  |  |  |  |  |  |  |  | 12,000,000 us-gaap_InvestmentIncomeNonoperating / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | (13,000,000)us-gaap_InvestmentIncomeNonoperating / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 3,000,000 us-gaap_InvestmentIncomeNonoperating / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember
Equity in net income (losses) of investees, net |  |  |  |  |  |  |  |  | 8,843,000,000 us-gaap_IncomeLossFromEquityMethodInvestments / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 7,540,000,000 us-gaap_IncomeLossFromEquityMethodInvestments / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 6,536,000,000 us-gaap_IncomeLossFromEquityMethodInvestments / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember
Other income (expense), net |  |  |  |  |  |  |  |  | 0 us-gaap_OtherNonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 us-gaap_OtherNonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 us-gaap_OtherNonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember
Nonoperating income (Expense), Total |  |  |  |  |  |  |  |  | 8,844,000,000 us-gaap_NonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 7,516,000,000 us-gaap_NonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 6,516,000,000 us-gaap_NonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember
Income (loss) before income taxes |  |  |  |  |  |  |  |  | 8,844,000,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 7,516,000,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 6,516,000,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember
Income tax (expense) benefit |  |  |  |  |  |  |  |  | 0 us-gaap_IncomeTaxExpenseBenefit / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 9,000,000 us-gaap_IncomeTaxExpenseBenefit / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 7,000,000 us-gaap_IncomeTaxExpenseBenefit / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember
Net income (loss) |  |  |  |  |  |  |  |  | 8,844,000,000 us-gaap_ProfitLoss / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 7,525,000,000 us-gaap_ProfitLoss / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 6,523,000,000 us-gaap_ProfitLoss / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember
Net (income) loss attributable to noncontrolling interests and redeemable subsidiary preferred stock |  |  |  |  |  |  |  |  | 0 cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 0 cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember
Net income (loss) attributable to Parent |  |  |  |  |  |  |  |  | 8,844,000,000 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 7,525,000,000 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 6,523,000,000 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember
Comprehensive income attributable to Parent |  |  |  |  |  |  |  |  | 8,807,000,000 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 7,521,000,000 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember | 6,523,000,000 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = cmcsa_ComcastHoldingsMember
CCCL Parent [Member] |  |  |  |  |  |  |  |  |  |  |
Service revenue |  |  |  |  |  |  |  |  | 0 us-gaap_SalesRevenueServicesNet / dei_LegalEntityAxis = cmcsa_CcclParentMember | 0 us-gaap_SalesRevenueServicesNet / dei_LegalEntityAxis = cmcsa_CcclParentMember | 0 us-gaap_SalesRevenueServicesNet / dei_LegalEntityAxis = cmcsa_CcclParentMember
Management fee revenue |  |  |  |  |  |  |  |  | 921,000,000 us-gaap_ManagementFeesRevenue / dei_LegalEntityAxis = cmcsa_CcclParentMember | 874,000,000 us-gaap_ManagementFeesRevenue / dei_LegalEntityAxis = cmcsa_CcclParentMember | 827,000,000 us-gaap_ManagementFeesRevenue / dei_LegalEntityAxis = cmcsa_CcclParentMember
Revenue |  |  |  |  |  |  |  |  | 921,000,000 us-gaap_Revenues / dei_LegalEntityAxis = cmcsa_CcclParentMember | 874,000,000 us-gaap_Revenues / dei_LegalEntityAxis = cmcsa_CcclParentMember | 827,000,000 us-gaap_Revenues / dei_LegalEntityAxis = cmcsa_CcclParentMember
Programming and production |  |  |  |  |  |  |  |  | 0 cmcsa_ProgrammingAndProductionCosts / dei_LegalEntityAxis = cmcsa_CcclParentMember | 0 cmcsa_ProgrammingAndProductionCosts / dei_LegalEntityAxis = cmcsa_CcclParentMember | 0 cmcsa_ProgrammingAndProductionCosts / dei_LegalEntityAxis = cmcsa_CcclParentMember
Other operating and administrative |  |  |  |  |  |  |  |  | 921,000,000 cmcsa_OtherOperatingAndAdministrative / dei_LegalEntityAxis = cmcsa_CcclParentMember | 874,000,000 cmcsa_OtherOperatingAndAdministrative / dei_LegalEntityAxis = cmcsa_CcclParentMember | 827,000,000 cmcsa_OtherOperatingAndAdministrative / dei_LegalEntityAxis = cmcsa_CcclParentMember
Advertising, marketing and promotion |  |  |  |  |  |  |  |  | 0 us-gaap_MarketingAndAdvertisingExpense / dei_LegalEntityAxis = cmcsa_CcclParentMember | 0 us-gaap_MarketingAndAdvertisingExpense / dei_LegalEntityAxis = cmcsa_CcclParentMember | 0 us-gaap_MarketingAndAdvertisingExpense / dei_LegalEntityAxis = cmcsa_CcclParentMember
Depreciation |  |  |  |  |  |  |  |  | 0 us-gaap_Depreciation / dei_LegalEntityAxis = cmcsa_CcclParentMember | 0 us-gaap_Depreciation / dei_LegalEntityAxis = cmcsa_CcclParentMember | 0 us-gaap_Depreciation / dei_LegalEntityAxis = cmcsa_CcclParentMember
Amortization |  |  |  |  |  |  |  |  | 0 us-gaap_AmortizationOfIntangibleAssets / dei_LegalEntityAxis = cmcsa_CcclParentMember | 0 us-gaap_AmortizationOfIntangibleAssets / dei_LegalEntityAxis = cmcsa_CcclParentMember | 0 us-gaap_AmortizationOfIntangibleAssets / dei_LegalEntityAxis = cmcsa_CcclParentMember
Costs and expenses, total |  |  |  |  |  |  |  |  | 921,000,000 us-gaap_CostsAndExpenses / dei_LegalEntityAxis = cmcsa_CcclParentMember | 874,000,000 us-gaap_CostsAndExpenses / dei_LegalEntityAxis = cmcsa_CcclParentMember | 827,000,000 us-gaap_CostsAndExpenses / dei_LegalEntityAxis = cmcsa_CcclParentMember
Operating income (loss) |  |  |  |  |  |  |  |  | 0 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = cmcsa_CcclParentMember | 0 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = cmcsa_CcclParentMember | 0 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = cmcsa_CcclParentMember
Interest expense |  |  |  |  |  |  |  |  | (176,000,000)us-gaap_InterestExpense / dei_LegalEntityAxis = cmcsa_CcclParentMember | (212,000,000)us-gaap_InterestExpense / dei_LegalEntityAxis = cmcsa_CcclParentMember | (329,000,000)us-gaap_InterestExpense / dei_LegalEntityAxis = cmcsa_CcclParentMember
Investment income (loss), net |  |  |  |  |  |  |  |  | 0 us-gaap_InvestmentIncomeNonoperating / dei_LegalEntityAxis = cmcsa_CcclParentMember | 0 us-gaap_InvestmentIncomeNonoperating / dei_LegalEntityAxis = cmcsa_CcclParentMember | 0 us-gaap_InvestmentIncomeNonoperating / dei_LegalEntityAxis = cmcsa_CcclParentMember
Equity in net income (losses) of investees, net |  |  |  |  |  |  |  |  | 8,273,000,000 us-gaap_IncomeLossFromEquityMethodInvestments / dei_LegalEntityAxis = cmcsa_CcclParentMember | 7,430,000,000 us-gaap_IncomeLossFromEquityMethodInvestments / dei_LegalEntityAxis = cmcsa_CcclParentMember | 6,665,000,000 us-gaap_IncomeLossFromEquityMethodInvestments / dei_LegalEntityAxis = cmcsa_CcclParentMember
Other income (expense), net |  |  |  |  |  |  |  |  | 0 us-gaap_OtherNonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_CcclParentMember | 2,000,000 us-gaap_OtherNonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_CcclParentMember | 0 us-gaap_OtherNonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_CcclParentMember
Nonoperating income (Expense), Total |  |  |  |  |  |  |  |  | 8,097,000,000 us-gaap_NonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_CcclParentMember | 7,220,000,000 us-gaap_NonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_CcclParentMember | 6,336,000,000 us-gaap_NonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_CcclParentMember
Income (loss) before income taxes |  |  |  |  |  |  |  |  | 8,097,000,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / dei_LegalEntityAxis = cmcsa_CcclParentMember | 7,220,000,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / dei_LegalEntityAxis = cmcsa_CcclParentMember | 6,336,000,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / dei_LegalEntityAxis = cmcsa_CcclParentMember
Income tax (expense) benefit |  |  |  |  |  |  |  |  | 62,000,000 us-gaap_IncomeTaxExpenseBenefit / dei_LegalEntityAxis = cmcsa_CcclParentMember | 73,000,000 us-gaap_IncomeTaxExpenseBenefit / dei_LegalEntityAxis = cmcsa_CcclParentMember | 115,000,000 us-gaap_IncomeTaxExpenseBenefit / dei_LegalEntityAxis = cmcsa_CcclParentMember
Net income (loss) |  |  |  |  |  |  |  |  | 8,159,000,000 us-gaap_ProfitLoss / dei_LegalEntityAxis = cmcsa_CcclParentMember | 7,293,000,000 us-gaap_ProfitLoss / dei_LegalEntityAxis = cmcsa_CcclParentMember | 6,451,000,000 us-gaap_ProfitLoss / dei_LegalEntityAxis = cmcsa_CcclParentMember
Net (income) loss attributable to noncontrolling interests and redeemable subsidiary preferred stock |  |  |  |  |  |  |  |  | 0 cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock / dei_LegalEntityAxis = cmcsa_CcclParentMember | 0 cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock / dei_LegalEntityAxis = cmcsa_CcclParentMember | 0 cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock / dei_LegalEntityAxis = cmcsa_CcclParentMember
Net income (loss) attributable to Parent |  |  |  |  |  |  |  |  | 8,159,000,000 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = cmcsa_CcclParentMember | 7,293,000,000 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = cmcsa_CcclParentMember | 6,451,000,000 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = cmcsa_CcclParentMember
Comprehensive income attributable to Parent |  |  |  |  |  |  |  |  | 8,162,000,000 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = cmcsa_CcclParentMember | 7,276,000,000 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = cmcsa_CcclParentMember | 6,460,000,000 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = cmcsa_CcclParentMember
Combined CCHMO Parents [Member] |  |  |  |  |  |  |  |  |  |  |
Service revenue |  |  |  |  |  |  |  |  | 0 us-gaap_SalesRevenueServicesNet / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 0 us-gaap_SalesRevenueServicesNet / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 0 us-gaap_SalesRevenueServicesNet / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember
Management fee revenue |  |  |  |  |  |  |  |  | 582,000,000 us-gaap_ManagementFeesRevenue / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 548,000,000 us-gaap_ManagementFeesRevenue / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 516,000,000 us-gaap_ManagementFeesRevenue / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember
Revenue |  |  |  |  |  |  |  |  | 582,000,000 us-gaap_Revenues / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 548,000,000 us-gaap_Revenues / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 516,000,000 us-gaap_Revenues / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember
Programming and production |  |  |  |  |  |  |  |  | 0 cmcsa_ProgrammingAndProductionCosts / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 0 cmcsa_ProgrammingAndProductionCosts / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 0 cmcsa_ProgrammingAndProductionCosts / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember
Other operating and administrative |  |  |  |  |  |  |  |  | 582,000,000 cmcsa_OtherOperatingAndAdministrative / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 548,000,000 cmcsa_OtherOperatingAndAdministrative / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 516,000,000 cmcsa_OtherOperatingAndAdministrative / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember
Advertising, marketing and promotion |  |  |  |  |  |  |  |  | 0 us-gaap_MarketingAndAdvertisingExpense / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 0 us-gaap_MarketingAndAdvertisingExpense / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 0 us-gaap_MarketingAndAdvertisingExpense / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember
Depreciation |  |  |  |  |  |  |  |  | 0 us-gaap_Depreciation / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 0 us-gaap_Depreciation / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 0 us-gaap_Depreciation / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember
Amortization |  |  |  |  |  |  |  |  | 0 us-gaap_AmortizationOfIntangibleAssets / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 0 us-gaap_AmortizationOfIntangibleAssets / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 0 us-gaap_AmortizationOfIntangibleAssets / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember
Costs and expenses, total |  |  |  |  |  |  |  |  | 582,000,000 us-gaap_CostsAndExpenses / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 548,000,000 us-gaap_CostsAndExpenses / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 516,000,000 us-gaap_CostsAndExpenses / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember
Operating income (loss) |  |  |  |  |  |  |  |  | 0 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 0 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 0 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember
Interest expense |  |  |  |  |  |  |  |  | (118,000,000)us-gaap_InterestExpense / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | (126,000,000)us-gaap_InterestExpense / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | (135,000,000)us-gaap_InterestExpense / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember
Investment income (loss), net |  |  |  |  |  |  |  |  | 0 us-gaap_InvestmentIncomeNonoperating / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 0 us-gaap_InvestmentIncomeNonoperating / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 0 us-gaap_InvestmentIncomeNonoperating / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember
Equity in net income (losses) of investees, net |  |  |  |  |  |  |  |  | 6,333,000,000 us-gaap_IncomeLossFromEquityMethodInvestments / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 5,473,000,000 us-gaap_IncomeLossFromEquityMethodInvestments / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 4,909,000,000 us-gaap_IncomeLossFromEquityMethodInvestments / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember
Other income (expense), net |  |  |  |  |  |  |  |  | 0 us-gaap_OtherNonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 0 us-gaap_OtherNonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 0 us-gaap_OtherNonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember
Nonoperating income (Expense), Total |  |  |  |  |  |  |  |  | 6,215,000,000 us-gaap_NonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 5,347,000,000 us-gaap_NonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 4,774,000,000 us-gaap_NonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember
Income (loss) before income taxes |  |  |  |  |  |  |  |  | 6,215,000,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 5,347,000,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 4,774,000,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember
Income tax (expense) benefit |  |  |  |  |  |  |  |  | 41,000,000 us-gaap_IncomeTaxExpenseBenefit / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 44,000,000 us-gaap_IncomeTaxExpenseBenefit / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 47,000,000 us-gaap_IncomeTaxExpenseBenefit / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember
Net income (loss) |  |  |  |  |  |  |  |  | 6,256,000,000 us-gaap_ProfitLoss / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 5,391,000,000 us-gaap_ProfitLoss / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 4,821,000,000 us-gaap_ProfitLoss / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember
Net (income) loss attributable to noncontrolling interests and redeemable subsidiary preferred stock |  |  |  |  |  |  |  |  | 0 cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 0 cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 0 cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember
Net income (loss) attributable to Parent |  |  |  |  |  |  |  |  | 6,256,000,000 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 5,391,000,000 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 4,821,000,000 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember
Comprehensive income attributable to Parent |  |  |  |  |  |  |  |  | 6,257,000,000 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 5,392,000,000 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember | 4,821,000,000 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = cmcsa_CombinedCchmoParentsMember
NBCUniversal Media Parent [Member] |  |  |  |  |  |  |  |  |  |  |
Service revenue |  |  |  |  |  |  |  |  | 0 us-gaap_SalesRevenueServicesNet / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 0 us-gaap_SalesRevenueServicesNet / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 0 us-gaap_SalesRevenueServicesNet / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember
Management fee revenue |  |  |  |  |  |  |  |  | 0 us-gaap_ManagementFeesRevenue / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 0 us-gaap_ManagementFeesRevenue / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 0 us-gaap_ManagementFeesRevenue / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember
Revenue |  |  |  |  |  |  |  |  | 0 us-gaap_Revenues / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 0 us-gaap_Revenues / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 0 us-gaap_Revenues / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember
Programming and production |  |  |  |  |  |  |  |  | 0 cmcsa_ProgrammingAndProductionCosts / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 0 cmcsa_ProgrammingAndProductionCosts / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 0 cmcsa_ProgrammingAndProductionCosts / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember
Other operating and administrative |  |  |  |  |  |  |  |  | 908,000,000 cmcsa_OtherOperatingAndAdministrative / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 855,000,000 cmcsa_OtherOperatingAndAdministrative / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 899,000,000 cmcsa_OtherOperatingAndAdministrative / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember
Advertising, marketing and promotion |  |  |  |  |  |  |  |  | 0 us-gaap_MarketingAndAdvertisingExpense / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 0 us-gaap_MarketingAndAdvertisingExpense / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 0 us-gaap_MarketingAndAdvertisingExpense / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember
Depreciation |  |  |  |  |  |  |  |  | 0 us-gaap_Depreciation / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 0 us-gaap_Depreciation / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 0 us-gaap_Depreciation / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember
Amortization |  |  |  |  |  |  |  |  | 0 us-gaap_AmortizationOfIntangibleAssets / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 0 us-gaap_AmortizationOfIntangibleAssets / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 0 us-gaap_AmortizationOfIntangibleAssets / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember
Costs and expenses, total |  |  |  |  |  |  |  |  | 908,000,000 us-gaap_CostsAndExpenses / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 855,000,000 us-gaap_CostsAndExpenses / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 899,000,000 us-gaap_CostsAndExpenses / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember
Operating income (loss) |  |  |  |  |  |  |  |  | (908,000,000)us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | (855,000,000)us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | (899,000,000)us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember
Interest expense |  |  |  |  |  |  |  |  | (479,000,000)us-gaap_InterestExpense / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | (488,000,000)us-gaap_InterestExpense / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | (430,000,000)us-gaap_InterestExpense / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember
Investment income (loss), net |  |  |  |  |  |  |  |  | (7,000,000)us-gaap_InvestmentIncomeNonoperating / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 3,000,000 us-gaap_InvestmentIncomeNonoperating / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 5,000,000 us-gaap_InvestmentIncomeNonoperating / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember
Equity in net income (losses) of investees, net |  |  |  |  |  |  |  |  | 4,523,000,000 us-gaap_IncomeLossFromEquityMethodInvestments / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 3,331,000,000 us-gaap_IncomeLossFromEquityMethodInvestments / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 4,402,000,000 us-gaap_IncomeLossFromEquityMethodInvestments / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember
Other income (expense), net |  |  |  |  |  |  |  |  | (4,000,000)us-gaap_OtherNonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | (1,000,000)us-gaap_OtherNonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | (14,000,000)us-gaap_OtherNonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember
Nonoperating income (Expense), Total |  |  |  |  |  |  |  |  | 4,033,000,000 us-gaap_NonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 2,845,000,000 us-gaap_NonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 3,963,000,000 us-gaap_NonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember
Income (loss) before income taxes |  |  |  |  |  |  |  |  | 3,125,000,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 1,990,000,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 3,064,000,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember
Income tax (expense) benefit |  |  |  |  |  |  |  |  | (10,000,000)us-gaap_IncomeTaxExpenseBenefit / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | (22,000,000)us-gaap_IncomeTaxExpenseBenefit / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | (9,000,000)us-gaap_IncomeTaxExpenseBenefit / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember
Net income (loss) |  |  |  |  |  |  |  |  | 3,115,000,000 us-gaap_ProfitLoss / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 1,968,000,000 us-gaap_ProfitLoss / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 3,055,000,000 us-gaap_ProfitLoss / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember
Net (income) loss attributable to noncontrolling interests and redeemable subsidiary preferred stock |  |  |  |  |  |  |  |  | 0 cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 0 cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 0 cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember
Net income (loss) attributable to Parent |  |  |  |  |  |  |  |  | 3,115,000,000 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 1,968,000,000 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 3,055,000,000 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember
Comprehensive income attributable to Parent |  |  |  |  |  |  |  |  | 2,972,000,000 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 2,017,000,000 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember | 3,068,000,000 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = cmcsa_NbcuniversalMediaParentMember
Comcast Non-Guarantor Subsidiaries [Member] |  |  |  |  |  |  |  |  |  |  |
Service revenue |  |  |  |  |  |  |  |  | 68,775,000,000 us-gaap_SalesRevenueServicesNet / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 64,657,000,000 us-gaap_SalesRevenueServicesNet / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 62,570,000,000 us-gaap_SalesRevenueServicesNet / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember
Management fee revenue |  |  |  |  |  |  |  |  | 0 us-gaap_ManagementFeesRevenue / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 0 us-gaap_ManagementFeesRevenue / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 0 us-gaap_ManagementFeesRevenue / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember
Revenue |  |  |  |  |  |  |  |  | 68,775,000,000 us-gaap_Revenues / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 64,657,000,000 us-gaap_Revenues / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 62,570,000,000 us-gaap_Revenues / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember
Programming and production |  |  |  |  |  |  |  |  | 20,912,000,000 cmcsa_ProgrammingAndProductionCosts / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 19,670,000,000 cmcsa_ProgrammingAndProductionCosts / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 19,929,000,000 cmcsa_ProgrammingAndProductionCosts / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember
Other operating and administrative |  |  |  |  |  |  |  |  | 19,150,000,000 cmcsa_OtherOperatingAndAdministrative / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 18,223,000,000 cmcsa_OtherOperatingAndAdministrative / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 17,381,000,000 cmcsa_OtherOperatingAndAdministrative / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember
Advertising, marketing and promotion |  |  |  |  |  |  |  |  | 5,078,000,000 us-gaap_MarketingAndAdvertisingExpense / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 4,969,000,000 us-gaap_MarketingAndAdvertisingExpense / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 4,831,000,000 us-gaap_MarketingAndAdvertisingExpense / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember
Depreciation |  |  |  |  |  |  |  |  | 6,303,000,000 us-gaap_Depreciation / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 6,224,000,000 us-gaap_Depreciation / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 6,120,000,000 us-gaap_Depreciation / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember
Amortization |  |  |  |  |  |  |  |  | 1,676,000,000 us-gaap_AmortizationOfIntangibleAssets / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 1,612,000,000 us-gaap_AmortizationOfIntangibleAssets / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 1,644,000,000 us-gaap_AmortizationOfIntangibleAssets / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember
Costs and expenses, total |  |  |  |  |  |  |  |  | 53,119,000,000 us-gaap_CostsAndExpenses / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 50,698,000,000 us-gaap_CostsAndExpenses / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 49,905,000,000 us-gaap_CostsAndExpenses / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember
Operating income (loss) |  |  |  |  |  |  |  |  | 15,656,000,000 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 13,959,000,000 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 12,665,000,000 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember
Interest expense |  |  |  |  |  |  |  |  | (212,000,000)us-gaap_InterestExpense / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | (214,000,000)us-gaap_InterestExpense / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | (174,000,000)us-gaap_InterestExpense / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember
Investment income (loss), net |  |  |  |  |  |  |  |  | 288,000,000 us-gaap_InvestmentIncomeNonoperating / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 586,000,000 us-gaap_InvestmentIncomeNonoperating / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 203,000,000 us-gaap_InvestmentIncomeNonoperating / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember
Equity in net income (losses) of investees, net |  |  |  |  |  |  |  |  | 3,212,000,000 us-gaap_IncomeLossFromEquityMethodInvestments / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 1,882,000,000 us-gaap_IncomeLossFromEquityMethodInvestments / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 4,014,000,000 us-gaap_IncomeLossFromEquityMethodInvestments / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember
Other income (expense), net |  |  |  |  |  |  |  |  | (211,000,000)us-gaap_OtherNonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | (363,000,000)us-gaap_OtherNonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 785,000,000 us-gaap_OtherNonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember
Nonoperating income (Expense), Total |  |  |  |  |  |  |  |  | 3,077,000,000 us-gaap_NonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 1,891,000,000 us-gaap_NonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 4,828,000,000 us-gaap_NonoperatingIncomeExpense / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember
Income (loss) before income taxes |  |  |  |  |  |  |  |  | 18,733,000,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 15,850,000,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 17,493,000,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember
Income tax (expense) benefit |  |  |  |  |  |  |  |  | (4,478,000,000)us-gaap_IncomeTaxExpenseBenefit / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | (4,457,000,000)us-gaap_IncomeTaxExpenseBenefit / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | (4,256,000,000)us-gaap_IncomeTaxExpenseBenefit / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember
Net income (loss) |  |  |  |  |  |  |  |  | 14,255,000,000 us-gaap_ProfitLoss / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 11,393,000,000 us-gaap_ProfitLoss / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 13,237,000,000 us-gaap_ProfitLoss / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember
Net (income) loss attributable to noncontrolling interests and redeemable subsidiary preferred stock |  |  |  |  |  |  |  |  | (212,000,000)cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | (319,000,000)cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | (1,662,000,000)cmcsa_NetIncomeLossAttributableToNoncontrollingInterestsAndRedeemableSubsidiaryPreferredStock / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember
Net income (loss) attributable to Parent |  |  |  |  |  |  |  |  | 14,043,000,000 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 11,074,000,000 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | 11,575,000,000 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember
Comprehensive income attributable to Parent |  |  |  |  |  |  |  |  | $ 13,980,000,000 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | $ 10,969,000,000 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember | $ 11,703,000,000 us-gaap_ComprehensiveIncomeNetOfTax / dei_LegalEntityAxis = cmcsa_ComcastNonGuarantorSubsidiariesMember

X
- Definition Amount of net (income) loss attributable to noncontrolling interest and dividends on redeemable subsidiary preferred stock. + References No definition available. + Details
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- Definition Other operating and administrative expense recognized in the period not presented separately. + References No definition available. + Details
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- Definition The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275 + Details
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- Definition Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Other Comprehensive Income -URI http://asc.fasb.org/extlink&oid=6519514 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Comprehensive Income -URI http://asc.fasb.org/extlink&oid=16317811 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=28358780&loc=d3e557-108580 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Net Income -URI http://asc.fasb.org/extlink&oid=6518256 + Details
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- Definition Total costs of sales and operating expenses for the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 + Details
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- Definition The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585 + Details
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- Definition This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses from ongoing operations, after income or loss from equity method investments, but before income taxes, extraordinary items, and noncontrolling interest. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 10 -Article 5 + Details
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