Accounts payable and accrued expenses related to trade creditors Accounts receivable, less allowance for doubtful accounts of $188 and $190 Accrued expenses and other current liabilities Property and equipment, accumulated depreciation Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income (Loss) Additional Paid in Capital Additional paid-in capital Additional Paid-In Capital Accounts receivable, allowance for doubtful accounts Amendment Flag Amortization Total assets Total assets ASSETS Total current assets Total current assets Current Assets: Cash and cash equivalents Cash and cash equivalents, end of period Cash and cash equivalents, beginning of period Increase (decrease) in cash and cash equivalents Increase (decrease) in cash and cash equivalents Note 10: Statement of Cash Flows-Supplemental Information Class of Stock [Domain] Commitments and Contingencies (Note 11) Note 11: Commitments and Contingencies Class A common stock Common Stock A A classification of Special Class A common stock. Class A Special common stock Common Stock A Special Class B common stock Common Stock B Dividends declared per common share attributable to Comcast Corporation stockholders Common stock, par value Common stock, authorized Common stock, issued Common stock, outstanding Common stock Comprehensive income attributable to Comcast Corporation Comprehensive income attributable to Comcast Corporation Comprehensive income Comprehensive income Contributions from and (distributions to) noncontrolling interests. Contributions from and (distributions to) noncontrolling interests Costs and Expenses Costs and Expenses, Total Costs and Expenses: Cumulative effect related to change in accounting principle on January 1, 2008 Current Fiscal Year End Date Current portion of long-term debt Deferred income taxes Depreciation Description of risk management strategies, derivatives in hedging activities and nonhedging derivative instruments, the assets, obligations, liabilities, revenues and expenses arising therefrom, and the amounts of and methodologies and assumptions used in determining the amounts of such items. This disclosure also contains the fair value amounts and methods used to estimate the fair values of all financial instruments. Note 6: Derivative Financial Instruments and Fair Value Measurements Dividends declared Dividends declared Document Information [Text Block] Document Period End Date Document Type Basic earnings per common share attributable to Comcast Corporation stockholders Diluted earnings per common share attributable to Comcast Corporation stockholders Note 3: Earnings Per Share Entity Central Index Key Entity Common Stock, Shares Outstanding Entity Filer Category Entity Registrant Name Entity [Text Block] Equity Component [Domain] Profit or loss as represented on the statement of changes in equity. Net income (loss) Other intangible assets, accumulated amortization Other intangible assets, net of accumulated amortization of $8,624 and $8,160 Goodwill Sum of operating profit and nonoperating income (expense) before income taxes, extraordinary items, cumulative effects of changes in accounting principles, and noncontrolling interest. Income before income taxes Income before income taxes Equity in net income (losses) of affiliates, net Income Statement [Abstract] Note 9: Income Taxes Income tax expense Income tax expense Franchise rights Interest Expense Interest expense Investment income (loss), net Includes all investments held by the company under the equity, cost and the fair value methods. Represents total on the balance sheet. Includes the components of investment income (loss), net. Note 4: Investments Total liabilities and equity Total liabilities and equity LIABILITIES AND EQUITY Total current liabilities Total current liabilities Current Liabilities: Long-term debt, less current portion Note 5: Long-Term Debt Long-term Investments Investments Stockholders' Equity Attributable to Noncontrolling Interest Noncontrolling interests Purchases of subsidiary shares from noncontrolling interests Purchases of subsidiary shares from noncontrolling interests Note 7: Noncontrolling Interests Sale (purchase) of subsidiary shares to (from) noncontrolling interests, net Net Cash Provided by (Used in) Financing Activities Net cash provided by (used in) financing activities Financing Activities Net Cash Provided by (Used in) Investing Activities Net cash provided by (used in) investing activities Investing Activities Net cash provided by operating activities Net income attributable to Comcast Corporation Net income attributable to Comcast Corporation Net (income) loss attributable to noncontrolling interests Net (income) loss attributable to noncontrolling interests Noncontrolling Interests Nonoperating Income (Expense) Nonoperating Income (Expense), Total Other Income (Expense): Notes to Financial Statements [Abstract] Notes to Financial Statements [Abstract] Operating expenses less depreciation and amortization. Operating (excluding depreciation and amortization) Operating income Operating income Note 1: Condensed Consolidated Financial Statements Other current assets Other noncurrent assets, net Employee benefit obligations, net of deferred taxes Cumulative translation adjustments Other comprehensive income (loss) Reclassification adjustments for losses (gains) included in net income attributable to Comcast Corporation, net of deferred taxes of $(3), $(2), $(17) and $(5) Reclassification adjustments for losses (gains) included in net income attributable to Comcast Corporation, net of deferred taxes of $(3), $(2), $(17) and $(5) Reclassification adjustments for losses (gains) included in net income attributable to Comcast Corporation, deferred taxes Holding gains (losses) during the period, net of deferred taxes of $(1), $3, $(2) and $9 Holding gains (losses) during the period, deferred taxes Other noncurrent liabilities Other income (expense) Payments for (Proceeds from) Other Investing Activities Other Repurchases of common stock Repurchases of common stock Dividends paid Dividends paid Acquisitions, net of cash acquired Acquisitions, net of cash acquired Cash paid for intangible assets Cash paid for intangible assets Purchases of investments Purchases of investments Capital expenditures Capital expenditures Preferred stock, authorized Preferred stock, issued Preferred stock-authorized, 20,000,000 shares; issued, zero Issuances of common stock Proceeds from borrowings Other Proceeds from sales of investments Net income from consolidated operations Net income from consolidated operations Property and equipment, net of accumulated depreciation of $26,716 and $23,235 Redeemable Noncontrolling Interests Redeemable Noncontrolling Interests Repurchases and repayments of debt Repurchases and repayments of debt Retained Earnings (Accumulated Deficit) Retained earnings Retained Earnings Revenue Note 13: Condensed Consolidating Financial Information Note 2: Recent Accounting Pronouncements Note 12: Financial Data by Business Segment Selling, general and administrative Short-term Investments Investments Class of Stock [Axis] Statement, Equity Components [Axis] Statement [Line Items] Statement of Cash Flows [Abstract] Statement of Financial Position [Abstract] Statement of Income and Comprehensive Income [Abstract] Statement of Stockholders' Equity [Abstract] Statement [Table] Total Comcast Corporation stockholders' equity Total Comcast Corporation stockholders' equity Beginning Balance Ending Balance Beginning Balance Total equity Equity: Note 8: Equity DO NOT USE StockholdersEquityStatementAbstract DO NOT USE StockholdersEquityStatementAbstract DO NOT USE StockholdersEquityStatementAbstract Share exchange Employee stock purchase plan Stock compensation plans Repurchase and retirement of common stock Repurchase and retirement of common stock Temporary Equity, Carrying Amount Redeemable noncontrolling interests Trading Symbol Treasury Stock at Cost Treasury stock common shares Treasury stock-365,460,750 Class A common shares and 70,934,764 Class A Special common shares Treasury stock-365,460,750 Class A common shares and 70,934,764 Class A Special common shares