Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Trading Arrangement: Trading Arrangement [Axis] Title of 12(b) Security Title of 12(b) Security Document Fiscal Year Focus Document Fiscal Year Focus Franchise rights Indefinite-Lived Franchise Rights 1.875% Notes due 2036 Notes 1.875 percent due 2036 [Member] Notes 1.875% due 2036 [Member] Adjustment to Compensation, Amount Adjustment to Compensation Amount Customer [Axis] Customer [Axis] Segment Reporting [Abstract] Segment Reporting [Abstract] Residential Connectivity Residential Connectivity [Member] Residential Connectivity [Member] Intangible Asset, Finite-Lived, and Capitalized Cost, Software to be Sold, Leased, or Marketed, Estimated Amortization Expense Intangible Asset, Finite-Lived, and Capitalized Cost, Software to be Sold, Leased, or Marketed, Estimated Amortization Expense [Table Text Block] Common stock Common Stock, Value, Issued Restatement Determination Date Restatement Determination Date External Customers External Customers [Member] External Customers Schedule of Other Balance Sheet Accounts Schedule Of Other Balance Sheet Accounts Related To Recognition Of Revenue [Table Text Block] Schedule Of Other Balance Sheet Accounts [Table Text Block] Domestic broadband Domestic Broadband [Member] Domestic Broadband Domestic wireless service Domestic Wireless Service [Member] Domestic Wireless Service Proceeds from divestiture of business Proceeds from Divestiture of Businesses Versant Separation (see Note 6) Goodwill, Divestiture Amendment Flag Amendment Flag Goodwill [Line Items] Goodwill [Line Items] Consolidated Entities [Axis] Consolidated Entities [Axis] Current Liabilities: Liabilities, Current [Abstract] Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding 1.250% Notes due 2040 Notes 1.250 percent due 2040 [Member] Notes 1.250% due 2040 [Member] Receivables Billing Status [Domain] Receivables Billing Status [Domain] 1.500% Notes due 2029 Notes 1.500 percent Due 2029 [Member] Notes 1.500% Due 2029 [Member] Disposal Group Classification [Axis] Disposal Group Classification [Axis] Investments and Variable Interest Entities Investment [Text Block] Programming and production Total programming and production costs Programming And Production Costs The amount of expense recognized in the period for costs associated with video programming and content acquisition and production costs. Programming expenses include the fees paid to license the programming distributed to video customers, such as the programming license fees charged by cable networks and fees charged for retransmission of the signals from local broadcast television stations. Production costs include the amortization of owned and acquired programming, sports rights, direct production costs, residual and participation payments, production overhead, costs associated with the distribution of programming to third-party networks and other distribution platforms, and on-air talent costs. It also includes the amortization of capitalized theatrical film production and acquisition costs and distribution expenses. Consolidated Entities [Domain] Consolidated Entities [Domain] Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Schedule of Cash and Cash Equivalents Schedule of Cash and Cash Equivalents [Table Text Block] Entity Address, State or Province Entity Address, State or Province Licensing agreements Licensing Agreements [Member] PEO Total Compensation Amount PEO Total Compensation Amount Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Currency translation adjustments, net of deferred taxes of $(15), $124, $(46), and $198 Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Weighted-average number of common shares outstanding – basic Weighted Average Number of Shares Outstanding, Basic Other comprehensive income (loss), net of tax (expense) benefit: Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax [Abstract] Accumulated impairment losses, beginning of period Accumulated impairment losses, end of period Goodwill, Impaired, Accumulated Impairment Loss Investments Noncurrent investments Long-Term Investments Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Notes Receivable Notes Receivable [Member] Number of reportable segments Number of Reportable Segments Total current liabilities Liabilities, Current Customer relationships Customer Relationships [Member] Investments [Abstract] Investments [Abstract] 3.550% Notes due 2036 Notes 3.550 percent due 2036 [Member] Notes 3.550 percent due 2036 5.250% Notes due 2040 Notes 5.250 percent due 2040 [Member] Notes 5.250 percent due 2040 Entity Address, City or Town Entity Address, City or Town Schedule of Cash Payments for Interest and Income Taxes Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Number of restricted share units granted (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Finance Receivable Program [Axis] Finance Receivable Program [Axis] Finance Receivable Program Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Unbilled Revenues Unbilled Revenues [Member] Versant Separation (see Note 6) Stockholders' Equity Note, Spinoff Transaction Document And Entity Information [Line Items] Document Information [Line Items] Assets Disposal Group, Including Discontinued Operation, Assets Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Class of Stock [Axis] Class of Stock [Axis] Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Receivable [Domain] Receivable [Domain] Other intangible assets - accumulated amortization Finite lived intangible asset, amortization Intangible Asset, Finite-Lived, Accumulated Amortization Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Other comprehensive income (loss) Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Equity method investments and certain retained distributions Equity Method Investments and Certain Retained Distributions Equity Method Investments and Certain Retained Distributions Noncash interest expense (income), net Noncash Interest Expense (Income) Net Represents noncash interest expense (income) items as adjustments to reconcile net income (loss) to cash provided by (used in) operating activities. Schedule of Long-Term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Earnings Per Share Earnings Per Share, Policy [Policy Text Block] Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Property and equipment and intangible assets accrued but not yet paid Capital Expenditures Incurred but Not yet Paid Schedule of Financial Data by Business Segment Segment Reporting [Table Text Block] Noncontrolling Interests Noncontrolling Interest [Member] Deferred gains (losses) on cash flow hedges, deferred taxes Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax Other Industries [Abstract] Other Industries [Abstract] Atairos Atairos [Member] Atairos [Member] Finance Receivable Program [Domain] Finance Receivable Program [Domain] Finance Receivable Program [Domain] Total Media Segment Media Segment [Member] Media Segment Employee benefit obligations and other, deferred taxes Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax RSU Granted During 2026 RSU Granted During 2026 [Member] RSU Granted During 2026 5.35% Notes due November 2027 5.35% Notes due November 2027 [Member] 5.35% Notes due November 2027 Film and television costs Film, Monetized On Its Own Capitalized Cost, And Entertainment, License Agreement For Program Material, Including Sports Rights Advances Total amounts of capitalized film cost for film predominantly monetized on its own and capitalized cost for rights acquired by broadcaster under license agreement for program material, including sports rights advances. Schedule of Investment Summary Summary Investment Holdings [Table Text Block] Document Period End Date Document Period End Date Changes in operating assets and liabilities, net of effects of acquisitions and divestitures: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] Completed, not released Film, Monetized on Its Own, Capitalized Cost, Completed and Not Released Net cash provided by (used in) investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Dividends payable (in dollars per share) Dividends Payable, Amount Per Share Debt instrument, face amount Debt Instrument, Face Amount 3.15% Notes due March 2026 3.15% Notes due March 2026 [Member] 3.15% Notes due March 2026 Equity and Share-Based Compensation Equity [Text Block] Costs and Expenses: Costs and Expenses [Abstract] Security Exchange Name Security Exchange Name Treasury stock, 919,026,355 Class A common shares Treasury Stock, Common, Value Eliminations Consolidation, Eliminations [Member] Transaction and transaction-related costs Transaction and Transaction-Related Costs Transaction and Transaction-Related Costs Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Shell Company Entity Shell Company Class B Common Stock Common Class B [Member] Consolidation Items [Domain] Consolidation Items [Domain] Sky Operations in Germany Sky Operations in Germany [Member] Sky Operations in Germany Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Name Outstanding Recovery, Individual Name Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Document Fiscal Period Focus Document Fiscal Period Focus Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Consolidated variable interest entity's liabilities included in condensed consolidated balance sheet Liabilities Trading Symbol Trading Symbol Capital expenditures Payments to Acquire Property, Plant, and Equipment Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Company Selected Measure Name Company Selected Measure Name Schedule of Restricted Cash Restrictions on Cash and Cash Equivalents [Table Text Block] Ownership percentage in variable interest entity Subsidiary, Ownership Percentage, Parent Unrecognized gains (losses) on employee benefit obligations and other Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Foreign currency translation and other Goodwill, Foreign Currency Translation Gain (Loss) And Other Goodwill, Foreign Currency Translation Gain (Loss) And Other Operating Activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Other operating and administrative Other Operating And Administrative Other operating and administrative expense recognized in the period not presented separately. Compensation Amount Outstanding Recovery Compensation Amount Individual: Individual [Axis] Weighted-average number of common shares outstanding – diluted Weighted Average Number of Shares Outstanding, Diluted Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Entity Emerging Growth Company Entity Emerging Growth Company Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] Redemption price, amount Debt Instrument, Redemption Price, Amount Debt Instrument, Redemption Price, Amount Disposal Group Name [Domain] Disposal Group Name [Domain] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Dividends payable Dividends Payable 2.0% Exchangeable Subordinated Debentures due 2029 Exchangeable Subordinated Debentures 2.0 Percent Due 2029 [Member] Exchangeable Subordinated Debentures 2.0% Due 2029 [Member] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] Current and noncurrent receivables, net Increase (Decrease) In Current And Noncurrent Receivables Net The increase (decrease) during the reporting period in the amount of current and noncurrent receivables. 0.250% Notes due 2029 Notes 0.250 percent Due 2029 [Member] Notes 0.250 percent Due 2029 Owned Film, Monetized On Its Own, Amortization Expense, Including Participations And Residuals Amount of amortization expense for capitalized film cost for film predominantly monetized on its own and participation and residuals expenses. Revenue from Contract with Customer [Abstract] Other agreements and rights Other Intangible Assets [Member] Other operating assets and liabilities Increase (Decrease) in Other Operating Assets and Liabilities, Net Award Timing Predetermined Award Timing Predetermined [Flag] Treasury Stock at Cost Treasury Stock, Common [Member] Intangible Asset, Goodwill and Other [Abstract] Noncurrent receivables, net (included in other noncurrent assets, net) Accounts Receivable, after Allowance for Credit Loss, Noncurrent Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Total carrying value of debt Debt and Lease Obligation Share-based compensation APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Remaining unfunded capital commitment Variable Interest Entity, Reporting Entity Involvement, Unfunded Capital Commitment Variable Interest Entity, Reporting Entity Involvement, Unfunded Capital Commitment Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Effect of dilutive securities Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements All Executive Categories All Executive Categories [Member] Repurchases of common stock under repurchase program and employee plans Stock Repurchased and Retired During Period, Value Proceeds from sales of businesses and investments Proceeds From Sales Of Businesses And Investments The cash inflow associated with the sale of businesses and investments, if any, during the period. Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Total fair value of debt Long-Term Debt, Fair Value Redeemable noncontrolling interests Balance, beginning of period Balance, end of period Redeemable Noncontrolling Interest, Equity, Carrying Amount Depreciation Depreciation Depreciation Plan Name [Domain] Plan Name [Domain] Schedule of Programming and Production Expense Schedule Of Programming And Production Cost [Table Text Block] Schedule Of Programming And Production Cost Scenario [Domain] Scenario [Domain] Intangible assets Disposal Group, Including Discontinued Operation, Intangible Assets Schedule of Weighted Average Common Shares Outstanding Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Debt Disclosure [Abstract] Debt Disclosure [Abstract] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Segment Information Segment Reporting [Text Block] 0.000% Notes due 2026 Notes 0.000 percent Due 2026 [Member] Notes 0.000 percent Due 2026 Expiration Date Trading Arrangement Expiration Date Schedule of Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Impact of foreign currency on cash, cash equivalents and restricted cash Effect of Exchange Rate on Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Total equity Balance, beginning of period Balance, end of period Accumulated other comprehensive income (loss), net of deferred taxes Equity, Including Portion Attributable to Noncontrolling Interest Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member] Business Combination [Line Items] Business Combination [Line Items] Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Common stock, authorized (in shares) Common Stock, Shares Authorized Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Exercise Price Award Exercise Price Investing Activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Segment Reporting [Line Items] Segment Reporting [Line Items] NBC Universal NBC Universal [Member] NBC Universal Unrecognized pretax compensation expense on nonvested awards Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount Document Quarterly Report Document Quarterly Report Other Other Programming And Production Expense Other Programming And Production Expense Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Licensed, including sports rights Entertainment, License Agreement For Program Material, Including Sports Rights Advances, Amortization Expense Amount of amortization expense for rights acquired by broadcaster under license agreement for program material, including sports rights advances. Segments [Domain] Segments [Domain] Total Accounts Receivable, after Allowance for Credit Loss Debt Debt Disclosure [Text Block] Advertising Advertising [Member] Scenario [Axis] Scenario [Axis] Repurchases and repayments of debt Repayments of Long-Term Debt Disposal Group Classification [Domain] Disposal Group Classification [Domain] Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Equity method Equity Method Investments Owned: Film, Capitalized Cost [Abstract] Business Combination [Table] Business Combination [Table] Equity Component [Domain] Equity Component [Domain] PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Owned Film, Monetized on Its Own, Capitalized Cost Business Combination, Asset Acquisition, Transaction between Entities under Common Control, and Joint Venture Formation [Abstract] Receivables, gross Accounts Receivable, before Allowance for Credit Loss, Current Total costs and expenses Costs and Expenses Adoption Date Trading Arrangement Adoption Date Stated interest rate (percent) Debt Instrument, Interest Rate, Stated Percentage Counterparty Name [Domain] Counterparty Name [Domain] Dividends declared Dividends, Common Stock, Cash Total Comcast Corporation shareholders’ equity Equity, Attributable to Parent Scenario, Plan Scenario, Plan [Member] Investment and other income (loss), net Investment and other income (loss), net Nonoperating Income (Expense) Disposal Group, Disposed of by Sale, Not Discontinued Operations Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] Assets Assets [Abstract] Title Trading Arrangement, Individual Title Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Other investments Other Investments Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Insider Trading Policies and Procedures [Line Items] Less: Allowance for credit losses Accounts Receivable, Allowance for Credit Loss, Current Other Proceeds from (Payment for) Other Financing Activity Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Deferred income taxes Deferred Income Tax Expense (Benefit) Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Antidilutive securities Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Restricted Stock Units (RSUs) Restricted Stock Units (RSUs) [Member] Goodwill Goodwill [Table Text Block] Goodwill gross, beginning of the period Goodwill gross, end of the period Goodwill, Gross Entity Central Index Key Entity Central Index Key Property and equipment - accumulated depreciation Property, Plant, and Equipment, Accumulated Depreciation, Depletion, and Amortization All Adjustments to Compensation All Adjustments to Compensation [Member] Other revenue Headquarters/Corporate and Other Segment Reporting, Reconciling Item, Corporate Nonsegment [Member] Equity [Abstract] Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Net cash provided by operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Total Business Services Connectivity Segment Business Services Connectivity Segment [Member] Business Services Connectivity Segment Less: Other comprehensive income (loss) attributable to noncontrolling interests Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest Liabilities Disposal Group, Including Discontinued Operation, Liabilities Other Stockholders' Equity, Other Licensed, including sports advances Entertainment, License Agreement For Program Material, Including Sports Rights Advances, Capitalized Cost Amount of capitalized cost for rights acquired by broadcaster under license agreement for program material, including sports rights advances. Income Statement [Abstract] Income Statement [Abstract] Document Transition Report Document Transition Report Ownership [Axis] Ownership [Axis] International connectivity International Connectivity [Member] International Connectivity Investment, Name [Axis] Investment, Name [Axis] Intersegment Eliminations Intersegment Eliminations [Member] Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Deferred revenue Deferred Revenue, Current Adjusted EBITDA Adjusted EBITDA The measure used to evaluate the profitability of operating segments. City Area Code City Area Code Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Document And Entity Information [Table] Document Information [Table] Video distribution programming Video Distribution Programming Expense Video Distribution Programming Expense All Individuals All Individuals [Member] Dividends paid Payments of Dividends Corporate Type [Axis] Corporate Type [Axis] Corporate Type Name Forgone Recovery, Individual Name Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Statement [Line Items] Statement [Line Items] Total assets Consolidated variable interest entity's assets included in condensed consolidated balance sheet Assets Entity [Domain] Entity [Domain] Preferred stock, issued (in shares) Preferred Stock, Shares Issued Variable Interest Entity, Not Primary Beneficiary Variable Interest Entity, Not Primary Beneficiary [Member] Operating Segments Operating Segments [Member] Interest expense Interest Expense, Nonoperating 0.750% Notes due 2032 Notes 0.750 percent due 2032 [Member] Notes 0.750% due 2032 [Member] Nonmarketable equity securities Equity Securities without Readily Determinable Fair Value, Amount In production and in development Film, Monetized On Its Own, Capitalized Cost, In Production And In Development Amounts of capitalized film cost incurred in production and in development of film predominantly monetized on its own PEO PEO [Member] Media, Studios and Theme Parks headquarters and other Media, Studios, Theme Parks Segments Headquarters And Other [Member] Media, Studios, Theme Parks Segments Headquarters And Other Recognized share-based compensation expense Share-Based Payment Arrangement, Expense Other noncurrent liabilities Other Liabilities, Noncurrent Goodwill Goodwill, beginning of period Goodwill, end of period Goodwill Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Total investments Investments Weighted-average fair value of restricted share units granted (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Realized and unrealized gains (losses) on equity securities, net Equity Securities, FV-NI, Gain (Loss) Retained Earnings Retained Earnings [Member] Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Common stock, shares outstanding at end of period (in shares) Common Stock, Shares, Outstanding Award Timing Disclosures [Line Items] Cumulative translation adjustments Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Diluted earnings per common share attributable to Comcast Corporation shareholders (in dollars per share) Earnings Per Share, Diluted Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Entity Current Reporting Status Entity Current Reporting Status Net cash provided by (used in) financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Total Shareholder Return Amount Total Shareholder Return Amount Contributions from (distributions to) noncontrolling interests, net Contributions From And Distributions To Noncontrolling Interests Attributable To Temporary Equity Contributions from and (distributions to) noncontrolling interests attributable to temporary equity. Consolidation, Less-than-Wholly-Owned Subsidiary, Parent Ownership Interest, Effect of Change [Table] Consolidation, Less-than-Wholly-Owned Subsidiary, Parent Ownership Interest, Effect of Change [Table] Amortization Amortization Intangible Asset, Finite-Lived, Amortization Expense Ownership [Domain] Ownership [Domain] Theatrical Theatrical [Member] Theatrical [Member] Universal Beijing Resort Term Loans Universal Beijing Resort Term Loans [Member] Universal Beijing Resort Term Loans [Member] Adjustments to reconcile net income to net cash provided by operating activities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Domestic distribution Domestic Distribution [Member] Domestic Distribution Property and equipment, net of accumulated depreciation of $62,017 and $60,754 Property, Plant, and Equipment, after Accumulated Depreciation, Depletion, and Amortization Financing Activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Revenue Revenue from Contract with Customer, Excluding Assessed Tax 3.250% Notes due 2032 Notes 3.250 percent due 2032 [Member] Notes 3.250 percent due 2032 Intangible Asset, Finite-Lived, Class [Axis] Intangible Asset, Finite-Lived, Class [Axis] Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Goodwill and Intangible Assets Intangible Asset and Goodwill [Text Block] Underlying Securities Award Underlying Securities Amount Revenue Revenue from Contract with Customer [Text Block] Content licensing Content Licensing [Member] Content Licensing [Member] Estimated Amortization Expense Intangible Asset, Finite-Lived, and Capitalized Cost, Software to be Sold, Leased, or Marketed, Estimated Amortization Expense [Abstract] Other Payment for (Proceeds from) Other Investing Activity Segment Reporting [Table] Segment Reporting [Table] Total Theme Parks Segment Theme Parks Segment [Member] Theme Parks Member Equity Method Investment [Table] Equity Method Investment [Table] Other current assets Other Assets, Current Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] All Trading Arrangements All Trading Arrangements [Member] Other Performance Measure, Amount Other Performance Measure, Amount Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Realized (gains) losses on cash flow hedges, deferred taxes Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax Operating income Operating Income (Loss) Amortization of owned film and television costs Film, Monetized on Its Own, Amortization Expense Current Fiscal Year End Date Current Fiscal Year End Date Equipment Installment Plan Equipment Installment Plan [Member] Equipment Installment Plan Loss on sale Gain (Loss) on Disposition of Business Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Cash flow hedges: Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax [Abstract] Significant Transactions Business Combination [Text Block] Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Cash dividends declared per common share (in dollars per share) Common Stock, Dividends, Per Share, Declared Entity File Number Entity File Number Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Issuances of common stock under employee plans Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture Other Other [Member] Other [Member] Payment for purchases of third party transferable tax credits Payment For Purchases Of Third Party Transferable Tax Credits Payment For Purchases Of Third Party Transferable Tax Credits Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Film and television costs, net Increase (Decrease) In Film And Television Costs Net Increase (Decrease) In Film And Television Costs Net Common stock, issued (in shares) Common Stock, Shares, Issued Measure: Measure [Axis] Condensed Consolidated Financial Statements Business Description and Basis of Presentation [Text Block] Scenario, Adjustment Scenario, Adjustment [Member] Treasury stock (in shares) Treasury Stock, Common, Shares Construction of Universal Beijing Resort Payments For Construction Of Theme Park The cash outflow associated with the construction of a theme park. Domestic wireless equipment Domestic Wireless Equipment [Member] Domestic Wireless Equipment Equity Components [Axis] Equity Components [Axis] Total Residential Connectivity & Platforms Segment Residential Connectivity And Platforms Segment [Member] Residential Connectivity And Platforms Segment Product and Service [Domain] Product and Service [Domain] Income taxes Income Tax Paid, after Refund Received Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Class A Common Stock, $0.01 par value Class A Common Stock Common Class A [Member] Entity Interactive Data Current Entity Interactive Data Current Less: Net income (loss) attributable to noncontrolling interests Less: Net income (loss) attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest International networks International Networks [Member] International Networks Deferred income taxes Deferred Income Tax Liabilities, Net Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Entity Small Business Entity Small Business Comprehensive income attributable to Comcast Corporation Comprehensive Income (Loss), Net of Tax, Attributable to Parent Corporate and other Corporate And Other, Type [Member] Corporate And Other, Type Contributions from (distributions to) noncontrolling interests, net Contributions From (Distributions To) Noncontrolling Interests Contributions From (Distributions To) Noncontrolling Interests Marketing and promotion Marketing and Advertising Expense Termination Date Trading Arrangement Termination Date Management Grant Management Grant [Member] Management Grant [Member] Spinoff Disposal Group, Disposed of Other than by Sale, Not Discontinued Operation, Spinoff [Member] Cash capital contributions for equity method investments Capital Contribution To VIE The cash outflow associated with a capital contribution to a VIE accounted for as an equity method investment Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] Employee benefit obligations and other, net of deferred taxes of $(5), $2, $—, and $20 Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Other noncurrent assets, net Other Assets, Noncurrent Document Type Document Type Acquisitions, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Currency translation adjustments, deferred taxes Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax Accrued expenses and other current liabilities Accrued Liabilities, Current Fair Value as of Grant Date Award Grant Date Fair Value Outstanding indebtedness Disposal Group, Including Discontinued Operation, Debt, Noncurrent Disposal Group, Including Discontinued Operation, Debt, Noncurrent Schedule of Goodwill [Table] Goodwill [Table] Domestic advertising Domestic Advertising [Member] Domestic Advertising Redeemable Noncontrolling Interests Increase (Decrease) in Temporary Equity [Roll Forward] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Arrangement Duration Trading Arrangement Duration Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Proceeds from borrowings Proceeds from Issuance of Long-Term Debt Local Phone Number Local Phone Number Supplemental Financial Information Additional Financial Information Disclosure [Text Block] Consolidation Items [Axis] Consolidation Items [Axis] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Registrant Name Entity Registrant Name Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Commitments and contingencies Commitments and Contingencies Finite lived intangible assets, gross Intangible Asset, Finite-Lived, before Accumulated Amortization Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] 2030 Intangible Asset, Finite-Lived, Estimated Amortization Expense, Year Four Equity in net income (losses) of investees, net Income (Loss) from Equity Method Investments Accounts payable and accrued expenses related to trade creditors Increase (Decrease) in Accounts Payable and Accrued Liabilities Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Executive Category: Executive Category [Axis] Receivable Type [Axis] Receivable Type [Axis] Vesting period Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period Goodwill [Roll Forward] Goodwill [Roll Forward] Counterparty Name [Axis] Counterparty Name [Axis] Liabilities and Equity Liabilities and Equity [Abstract] Intangible Asset, Finite-Lived, Class [Domain] Intangible Asset, Finite-Lived, Class [Domain] Award Type [Domain] Award Type [Domain] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Realized (gains) losses reclassified to net income, net of deferred taxes of $(3), $13, $(5), and $19 Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax 2027 Intangible Asset, Finite-Lived, Estimated Amortization Expense, Year One Ownership percentage Subsidiary, Ownership Percentage, Noncontrolling Owner Cash transferred to Versant, net Cash transferred to Versant, net Cash Transferred As Part Of Separation Agreement Cash Transferred As Part Of Separation Agreement PEO Name PEO Name Restricted cash included in other current assets and other noncurrent assets, net Restricted Cash Billing Status, Type [Axis] Billing Status, Type [Axis] Deferred gains (losses) on cash flow hedges Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member] Other Segment Reporting, Other Segment Item, Amount Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Entity Tax Identification Number Entity Tax Identification Number Legal Entity [Axis] Legal Entity [Axis] Programming and Production Costs Entertainment [Text Block] Deferred gains (losses), net of deferred taxes of $(3), $(15), $(5), and $(15) Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax Net (gain) loss on investment activity and other (Gain) Loss On Investments And Other Noncash (Income) Loss, Net Net (gain) loss on investment activity, including cash received from investees, and other noncash income (loss), net. Cash, cash equivalents and restricted cash, beginning of period Cash, cash equivalents and restricted cash, end of period Cash, cash equivalents and restricted cash, end of period Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Non-NEOs Non-NEOs [Member] Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Comprehensive income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Debt Instrument [Axis] Debt Instrument [Axis] Share-based compensation Share-Based Payment Arrangement, Noncash Expense 2028 Intangible Asset, Finite-Lived, Estimated Amortization Expense, Year Two Universal Beijing Resort Universal Beijing Resort [Member] Universal Beijing Resort [Member] Disposal Group Name [Axis] Disposal Group Name [Axis] Customer [Domain] Customer [Domain] Investment, Name [Domain] Investment, Name [Domain] Long-Term Debt, Type [Domain] Long-Term Debt, Type [Domain] Basic earnings per common share attributable to Comcast Corporation shareholders (in dollars per share) Earnings Per Share, Basic Repurchases of common stock under repurchase program and employee plans Payments for Repurchase of Common Stock Total current assets Assets, Current Insider Trading Arrangements [Line Items] Award Type [Axis] Award Type [Axis] 5.50% Notes due 2029 Notes 5.50 Percent Due 2029 [Member] Notes 5.50% Due 2029 [Member] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Receivables, net Receivables, net Accounts Receivable, after Allowance for Credit Loss, Current Retained earnings Retained Earnings (Accumulated Deficit) Product and Service [Axis] Product and Service [Axis] Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Common Stock Common Stock [Member] Film and television content: Film And Television Content [Abstract] Film And Television Content Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Cover [Abstract] Cover [Abstract] Reclassifications Reclassification, Comparability Adjustment [Policy Text Block] Assets held for sale Disposal Group, Held-for-Sale or Disposed of by Sale, Not Discontinued Operations [Member] Noncurrent deferred revenue (included in other noncurrent liabilities) Deferred Revenue, Noncurrent Equity Awards Adjustments Equity Awards Adjustments [Member] Total liabilities and equity Liabilities and Equity Employee Stock Option Share-Based Payment Arrangement, Option [Member] Current portion of debt Debt, Current Film and television costs Film, Monetized On Its Own, And Entertainment, License Agreement For Program Material, Including Sports Rights Advances, Capitalized Costs, Noncurrent Amount of capitalized film cost for film predominantly monetized on its own and capitalized cost for rights acquired by broadcaster under license agreement for program material, including sports rights advances, noncurrent. Loss reclassified out of AOCI Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax Noncontrolling interests Equity, Attributable to Noncontrolling Interest Segments [Axis] Segments [Axis] Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Plan Name [Axis] Plan Name [Axis] Versant Versant [Member] Versant Schedule of Receivables, Net Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Tabular List, Table Tabular List [Table Text Block] Additional paid-in capital Additional Paid in Capital Other income (loss), net Other Nonoperating Income (Expense) Cash paid for intangible assets Payments to Acquire Intangible Assets Senior Secured Notes Senior Secured Notes [Member] Senior Unsecured Notes [Member] 2029 Intangible Asset, Finite-Lived, Estimated Amortization Expense, Year Three Remaining six months of 2026 Intangible Asset, Finite-Lived, Estimated Amortization Expense, Remainder of Fiscal Year Name Awards Close in Time to MNPI Disclosures, Individual Name Equity: Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Purchases of investments Payments to Acquire Investments Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Schedule of Investment and Other Income (Loss), Net Components Of Investment And Other Income (Loss), Net [Table Text Block] Tabular disclosure of investment and other income (loss), net, including, but not limited to, equity in net income (losses) of investees, net, realized and unrealized gains (losses) on equity securities, net, and other income (loss), net. Preferred stock, authorized (in shares) Preferred Stock, Shares Authorized Preferred stock—authorized, 20,000,000 shares; issued, zero Preferred Stock, Value, Issued Adjustment to Compensation: Adjustment to Compensation [Axis] Net income (loss) Net Income (Loss) Attributable to Redeemable Noncontrolling Interest Corporate Type [Domain] Corporate Type [Domain] Corporate Type [Domain] Class of Stock [Domain] Class of Stock [Domain] Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Interest Interest Paid, Excluding Capitalized Interest, Operating Activity Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Conversion ratio (pers share) Shareholders Equity, Share Conversion Ratio Shareholders Equity, Share Conversion Ratio Aggregate Available Trading Arrangement, Securities Aggregate Available Amount RSU Granted Prior to 2026 RSU Granted Before 2026 [Member] RSU Granted Before 2026 Noncurrent portion of debt Long-Term Debt and Lease Obligation Name Measure Name Accounts payable and accrued expenses related to trade creditors Accounts Payable, Current Pay vs Performance Disclosure [Line Items] Debt Instrument [Line Items] Debt Instrument [Line Items] Released, less amortization Film, Monetized on Its Own, Capitalized Cost, Released Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Additional Paid-In Capital Additional Paid-in Capital [Member] Entity Filer Category Entity Filer Category Less: Current investments Short-Term Investments Name Trading Arrangement, Individual Name Cash and cash equivalents Cash and cash equivalents Cash and Cash Equivalent Schedule of Capitalized Film and Television Costs Schedule Of Capitalized Film And Television Costs [Table Text Block] Schedule of capitalized costs for film predominantly monetized on its own and for rights acquired by broadcaster under license agreement for program material, including sports rights advances, recorded at the balance sheet date. Company Selected Measure Amount Company Selected Measure Amount Cash distribution received from equity method investments Proceeds from Equity Method Investment, Distribution Unrealized gains (losses) recognized Equity Securities, FV-NI, Unrealized Gain (Loss) Depreciation and amortization Depreciation, Depletion and Amortization 0.250% Notes due 2027 Notes 0.250 percent Due 2027 [Member] Notes 0.250% Due 2027 [Member] Net income Net income Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Other Temporary Equity, Other Changes Current Assets: Assets, Current [Abstract] Non-PEO NEO Non-PEO NEO [Member] Senior Notes Senior Notes [Member] Entity Address, Address Line One Entity Address, Address Line One Income tax expense Income Tax Expense (Benefit) Total Studios Segment Studios Segment [Member] Studios Segment Video Video [Member] Video Net income (loss) Net Income (Loss), Including Portion Attributable to Nonredeemable Noncontrolling Interest Spinoff Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] Award Timing Method Award Timing Method [Text Block] Increase (decrease) in cash, cash equivalents and restricted cash Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Other intangible assets, net of accumulated amortization of $31,818 and $39,362 Other Intangible Assets, Net Variable Interest Entity, Primary Beneficiary Variable Interest Entity, Primary Beneficiary [Member] Net income attributable to Comcast Corporation Net Income (Loss) Attributable to Parent Long-Term Debt, Type [Axis] Long-Term Debt, Type [Axis] Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Goodwill Disposal Group, Including Discontinued Operation, Goodwill Statement [Table] Statement [Table] Restatement Determination Date: Restatement Determination Date [Axis] Schedule of Accumulated Other Comprehensive Income (Loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Revenues [Abstract] Revenues [Abstract] Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block]