v2.4.0.6
Condensed Consolidating Financial Information (Condensed Consolidating Statement of Income) (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended
Mar. 31, 2013
Mar. 31, 2012
Service revenue $ 15,310 $ 14,878
Management fee revenue 0 0
Revenue 15,310 14,878
Programming and production 4,663 4,737
Other operating and administrative 4,466 4,244
Advertising, marketing and promotion 1,147 1,209
Depreciation 1,566 1,529
Amortization 401 401
Costs and expenses, total 12,243 12,120
Operating income (loss) 3,067 2,758
Interest expense (653) (640)
Investment income (loss), net 72 92
Equity in net income (losses) of investees, net 11 3
Other income (expense), net 73 (16)
Nonoperating income (Expense), Total (497) (561)
Income (loss) before income taxes 2,570 2,197
Income tax (expense) benefit (925) (750)
Net income (loss) 1,645 1,447
Net (income) loss attributable to noncontrolling interests and redeemable subsidiary preferred stock (208) (223)
Net income (loss) attributable to Comcast Corporation 1,437 1,224
Comprehensive income attributable to Comcast Corporation 1,437 1,228
Comcast [Member]
    
Management fee revenue 218 204
Revenue 218 204
Other operating and administrative 98 92
Depreciation 7 7
Amortization 1 1
Costs and expenses, total 106 100
Operating income (loss) 112 104
Interest expense (376) (367)
Investment income (loss), net 1 1
Equity in net income (losses) of investees, net 1,608 1,394
Other income (expense), net (1)  
Nonoperating income (Expense), Total 1,232 1,028
Income (loss) before income taxes 1,344 1,132
Income tax (expense) benefit 93 92
Net income (loss) 1,437 1,224
Net income (loss) attributable to Comcast Corporation 1,437 1,224
Comprehensive income attributable to Comcast Corporation 1,437 1,227
Comcast Holdings [Member]
    
Interest expense (3) (8)
Investment income (loss), net (3)  
Equity in net income (losses) of investees, net 1,742 1,504
Nonoperating income (Expense), Total 1,736 1,496
Income (loss) before income taxes 1,736 1,496
Income tax (expense) benefit 2 3
Net income (loss) 1,738 1,499
Net income (loss) attributable to Comcast Corporation 1,738 1,499
Comprehensive income attributable to Comcast Corporation 1,738 1,499
CCCL Parent [Member]
    
Management fee revenue 212 200
Revenue 212 200
Other operating and administrative 212 200
Costs and expenses, total 212 200
Interest expense (78) (82)
Equity in net income (losses) of investees, net 1,763 1,543
Nonoperating income (Expense), Total 1,685 1,461
Income (loss) before income taxes 1,685 1,461
Income tax (expense) benefit 27 29
Net income (loss) 1,712 1,490
Net income (loss) attributable to Comcast Corporation 1,712 1,490
Comprehensive income attributable to Comcast Corporation 1,714 1,492
Combined CCHMO Parents [Member]
    
Management fee revenue 133 125
Revenue 133 125
Other operating and administrative 133 125
Costs and expenses, total 133 125
Interest expense (33) (36)
Equity in net income (losses) of investees, net 1,262 1,049
Nonoperating income (Expense), Total 1,229 1,013
Income (loss) before income taxes 1,229 1,013
Income tax (expense) benefit 11 13
Net income (loss) 1,240 1,026
Net income (loss) attributable to Comcast Corporation 1,240 1,026
Comprehensive income attributable to Comcast Corporation 1,240 1,026
NBCUniversal Media Parent [Member]
    
Service revenue   0
Revenue   0
Other operating and administrative 225 253
Costs and expenses, total 225 253
Operating income (loss) (225) (253)
Interest expense (120) (102)
Investment income (loss), net (4)  
Equity in net income (losses) of investees, net 709 743
Other income (expense), net   (1)
Nonoperating income (Expense), Total 585 640
Income (loss) before income taxes 360 387
Income tax (expense) benefit (5) (2)
Net income (loss) 355 385
Net income (loss) attributable to Comcast Corporation 355 385
Comprehensive income attributable to Comcast Corporation 333 386
Comcast Non-Guarantor Subsidiaries [Member]
    
Service revenue 15,310 14,878
Revenue 15,310 14,878
Programming and production 4,663 4,737
Other operating and administrative 4,361 4,103
Advertising, marketing and promotion 1,147 1,209
Depreciation 1,559 1,522
Amortization 400 400
Costs and expenses, total 12,130 11,971
Operating income (loss) 3,180 2,907
Interest expense (43) (45)
Investment income (loss), net 78 91
Equity in net income (losses) of investees, net 366 388
Other income (expense), net 74 (15)
Nonoperating income (Expense), Total 475 419
Income (loss) before income taxes 3,655 3,326
Income tax (expense) benefit (1,053) (885)
Net income (loss) 2,602 2,441
Net (income) loss attributable to noncontrolling interests and redeemable subsidiary preferred stock (208) (223)
Net income (loss) attributable to Comcast Corporation 2,394 2,218
Comprehensive income attributable to Comcast Corporation 2,407 2,216
Elimination and Consolidation Adjustments [Member]
    
Management fee revenue (563) (529)
Revenue (563) (529)
Other operating and administrative (563) (529)
Costs and expenses, total (563) (529)
Equity in net income (losses) of investees, net (7,439) (6,618)
Nonoperating income (Expense), Total (7,439) (6,618)
Income (loss) before income taxes (7,439) (6,618)
Net income (loss) (7,439) (6,618)
Net income (loss) attributable to Comcast Corporation (7,439) (6,618)
Comprehensive income attributable to Comcast Corporation $ (7,432) $ (6,618)