Accounts payable and accrued expenses related to trade creditors Accounts receivable, less allowance for doubtful accounts of $192 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 [Member] Accumulated Other Comprehensive Income (Loss) Additional Paid in Capital Additional paid-in capital Additional Paid-In Capital Accounts receivable, allowance for doubtful accounts Amendment Description 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 Dividends declared Dividends declared Note 9: Statement of Cash Flows-Supplemental Information Class of Stock [Domain] Commitments and Contingencies (Note 10) Note 10: Commitments and Contingencies Class A common stock Common Stock A 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 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 Note 6: Derivative Financial Instruments and Fair Value Measurements 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 Current Reporting Status Entity Filer Category Entity Public Float Entity Registrant Name Entity [Text Block] Entity Voluntary Filers Entity Well-known Seasoned Issuer Equity Component [Domain] Net income (loss) Other intangible assets, accumulated amortization Other intangible assets, net of accumulated amortization of $8,299 and $8,160 Goodwill Income before income taxes Income before income taxes Equity in net income (losses) of affiliates, net Income Statement [Abstract] Income tax expense Income tax expense Franchise rights Interest expense Interest expense 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 Minority Interest Noncontrolling interests Note 7: Noncontrolling Interests 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] 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 $(2), $(1), $(14) and $(3) Reclassification adjustments for losses (gains) included in net income attributable to Comcast Corporation, net of deferred taxes of $(2), $(1), $(14) and $(3) 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 $(2), $3, $(1) and $6 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 $25,544 and $23,235 Purchases of subsidiary shares from noncontrolling interests Purchases of subsidiary shares from noncontrolling interests Sale (purchase) of subsidiary shares to (from) noncontrolling interests, net Sale (purchase) of subsidiary shares to (from) noncontrolling interests, net Redeemable Noncontrolling Interests Repurchases and repayments of debt Repurchases and repayments of debt Retained Earnings (Accumulated Deficit) Retained earnings Retained Earnings Revenue Note 12: Condensed Consolidating Financial Information Note 2: Recent Accounting Pronouncements Note 11: Financial Data by Business Segment Selling, general and administrative Investments Statement, 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] Share exchange Share exchange Total Comcast Corporation stockholders' equity Total Comcast Corporation stockholders' equity Total equity Ending Balance Beginning Balance Total equity Equity: Note 8: Equity Accumulated Other Comprehensive Income (Loss) 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