v2.4.0.6
Condensed Consolidating Financial Information (Condensed Consolidating Statement of Income) (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended 6 Months Ended
Jun. 30, 2012
Jun. 30, 2011
Jun. 30, 2012
Jun. 30, 2011
Service revenue $ 15,211 $ 14,333 $ 30,089 $ 26,461
Management fee revenue 0 0 0 0
Revenue 15,211 14,333 30,089 26,461
Operating costs and expenses 10,207 9,532 20,397 17,594
Depreciation 1,516 1,478 3,045 2,964
Amortization 409 385 810 741
Costs and expenses, total 12,132 11,395 24,252 21,299
Operating income (loss) 3,079 2,938 5,837 5,162
Interest expense (625) (621) (1,265) (1,226)
Investment income (loss), net 8 61 100 150
Equity in net income (losses) of investees, net 29 37 32 0
Other income (expense), net (47) (34) (63) (70)
Nonoperating income (Expense), Total (635) (557) (1,196) (1,146)
Income (loss) before income taxes 2,444 2,381 4,641 4,016
Income tax (expense) benefit (811) (1,014) (1,561) (1,610)
Net income (loss) 1,633 1,367 3,080 2,406
Net (income) loss attributable to noncontrolling interests (285) (345) (508) (441)
Net income (loss) attributable to Comcast Corporation 1,348 1,022 2,572 1,965
Comprehensive income attributable to Comcast Corporation 1,326 1,014 2,554 1,959
Comcast [Member]
        
Service revenue 0 0 0 0
Management fee revenue 210 200 414 398
Revenue 210 200   398
Operating costs and expenses 99 89 191 237
Depreciation 8 7 15 14
Amortization 1 1 2 2
Costs and expenses, total 108 97   253
Operating income (loss) 102 103 206 145
Interest expense (354) (358) (721) (719)
Investment income (loss), net 2 2 3 3
Equity in net income (losses) of investees, net 1,511 1,186 2,905 2,347
Other income (expense), net 0 1 0 (16)
Nonoperating income (Expense), Total 1,159 831    
Income (loss) before income taxes 1,261 934 2,393 1,760
Income tax (expense) benefit 87 88 179 205
Net income (loss) 1,348 1,022 2,572 1,965
Net (income) loss attributable to noncontrolling interests 0 0 0 0
Net income (loss) attributable to Comcast Corporation 1,348 1,022 2,572 1,965
Comprehensive income attributable to Comcast Corporation 1,326 1,014 2,554 1,959
CCCL Parent [Member]
        
Service revenue 0 0 0 0
Management fee revenue 205 195 405 380
Revenue 205 195   380
Operating costs and expenses 205 195 405 380
Depreciation 0 0 0 0
Amortization 0 0 0 0
Costs and expenses, total 205 195   380
Operating income (loss) 0 0 0 0
Interest expense (83) (82) (165) (173)
Investment income (loss), net 0 0 0 0
Equity in net income (losses) of investees, net 1,679 1,336 3,222 2,659
Other income (expense), net 0 0 0 0
Nonoperating income (Expense), Total 1,596 1,254    
Income (loss) before income taxes 1,596 1,254 3,057 2,486
Income tax (expense) benefit 29 28 58 60
Net income (loss) 1,625 1,282 3,115 2,546
Net (income) loss attributable to noncontrolling interests 0 0 0 0
Net income (loss) attributable to Comcast Corporation 1,625 1,282 3,115 2,546
Comprehensive income attributable to Comcast Corporation 1,627 1,284 3,119 2,550
Combined CCHMO Parents [Member]
        
Service revenue 0 0 0 0
Management fee revenue 127 119 252 234
Revenue 127 119   234
Operating costs and expenses 127 119 252 234
Depreciation 0 0 0 0
Amortization 0 0 0 0
Costs and expenses, total 127 119   234
Operating income (loss) 0 0 0 0
Interest expense (33) (43) (69) (86)
Investment income (loss), net 0 0 0 0
Equity in net income (losses) of investees, net 1,326 805 2,375 1,599
Other income (expense), net 0 0 0 0
Nonoperating income (Expense), Total 1,293 762    
Income (loss) before income taxes 1,293 762 2,306 1,513
Income tax (expense) benefit 11 15 24 30
Net income (loss) 1,304 777 2,330 1,543
Net (income) loss attributable to noncontrolling interests 0 0 0 0
Net income (loss) attributable to Comcast Corporation 1,304 777 2,330 1,543
Comprehensive income attributable to Comcast Corporation 1,304 777 2,330 1,543
Comcast Holdings [Member]
        
Service revenue 0 0 0 0
Management fee revenue 0 0 0 0
Revenue 0 0   0
Operating costs and expenses 0 0 0 5
Depreciation 0 0 0 0
Amortization 0 0 0 0
Costs and expenses, total 0 0   5
Operating income (loss) 0 0 0 (5)
Interest expense (8) (8) (16) (16)
Investment income (loss), net 1 1 1 5
Equity in net income (losses) of investees, net 1,620 1,424 3,124 2,716
Other income (expense), net 0 0 0 1
Nonoperating income (Expense), Total 1,613 1,417    
Income (loss) before income taxes 1,613 1,417 3,109 2,701
Income tax (expense) benefit 2 2 5 5
Net income (loss) 1,615 1,419 3,114 2,706
Net (income) loss attributable to noncontrolling interests 0 0 0 0
Net income (loss) attributable to Comcast Corporation 1,615 1,419 3,114 2,706
Comprehensive income attributable to Comcast Corporation 1,615 1,419 3,114 2,706
Comcast Non-Guarantor Subsidiaries [Member]
        
Service revenue 15,211 14,333 30,089 26,461
Management fee revenue 0 0 0 0
Revenue 15,211 14,333   26,461
Operating costs and expenses 10,318 9,643 20,620 17,750
Depreciation 1,508 1,471 3,030 2,950
Amortization 408 384 808 739
Costs and expenses, total 12,234 11,498   21,439
Operating income (loss) 2,977 2,835 5,631 5,022
Interest expense (147) (130) (294) (232)
Investment income (loss), net 5 58 96 142
Equity in net income (losses) of investees, net 29 37 32 0
Other income (expense), net (47) (35) (63) (55)
Nonoperating income (Expense), Total (160) (70)    
Income (loss) before income taxes 2,817 2,765 5,402 4,877
Income tax (expense) benefit (940) (1,147) (1,827) (1,910)
Net income (loss) 1,877 1,618 3,575 2,967
Net (income) loss attributable to noncontrolling interests (285) (345) (508) (441)
Net income (loss) attributable to Comcast Corporation 1,592 1,273 3,067 2,526
Comprehensive income attributable to Comcast Corporation 1,588 1,270 3,062 2,525
Elimination and Consolidation Adjustments [Member]
        
Service revenue 0 0 0 0
Management fee revenue (542) (514) (1,071) (1,012)
Revenue (542) (514)   (1,012)
Operating costs and expenses (542) (514) (1,071) (1,012)
Depreciation 0 0 0 0
Amortization 0 0 0 0
Costs and expenses, total (542) (514)   (1,012)
Operating income (loss) 0 0 0 0
Interest expense 0 0 0 0
Investment income (loss), net 0 0 0 0
Equity in net income (losses) of investees, net (6,136) (4,751) (11,626) (9,321)
Other income (expense), net 0 0 0 0
Nonoperating income (Expense), Total (6,136) (4,751)    
Income (loss) before income taxes (6,136) (4,751) (11,626) (9,321)
Income tax (expense) benefit 0 0 0 0
Net income (loss) (6,136) (4,751) (11,626) (9,321)
Net (income) loss attributable to noncontrolling interests 0 0 0 0
Net income (loss) attributable to Comcast Corporation (6,136) (4,751) (11,626) (9,321)
Comprehensive income attributable to Comcast Corporation $ (6,134) $ (4,750) $ (11,625) $ (9,324)