v3.3.1.900
Condensed Consolidating Financial Information (Condensed Consolidating Statement of Income) (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Dec. 31, 2015
Sep. 30, 2015
Jun. 30, 2015
Mar. 31, 2015
Dec. 31, 2014
Sep. 30, 2014
Jun. 30, 2014
Mar. 31, 2014
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Service revenue                 $ 74,510 $ 68,775 $ 64,657
Revenue $ 19,245 $ 18,669 $ 18,743 $ 17,853 $ 17,732 $ 16,791 $ 16,844 $ 17,408 74,510 68,775 64,657
Costs and Expenses:                      
Programming and production                 22,550 20,912 19,670
Other operating and administrative                 21,339 19,854 18,575
Advertising, marketing and promotion                 5,943 5,086 4,978
Depreciation                 6,781 6,337 6,254
Amortization                 1,899 1,682 1,617
Costs and expenses, total                 58,512 53,871 51,094
Operating income (loss) 4,002 4,001 4,105 3,890 3,787 3,745 3,804 3,568 15,998 14,904 13,563
Other Income (Expense):                      
Interest expense                 (2,702) (2,617) (2,574)
Investment income (loss), net                 81 296 576
Equity in net income (losses) of investees, net                 (325) 97 (86)
Other income (expense), net                 320 (215) (364)
Nonoperating income (Expense), Total                 (2,626) (2,439) (2,448)
Income (loss) before income taxes                 13,372 12,465 11,115
Income tax (expense) benefit                 (4,959) (3,873) (3,980)
Net income (loss)                 8,413 8,592 7,135
Net (income) loss attributable to noncontrolling interests and redeemable subsidiary preferred stock                 (250) (212) (319)
Net income (loss) attributable to Parent $ 1,971 $ 1,996 $ 2,137 $ 2,059 $ 1,925 $ 2,592 $ 1,992 $ 1,871 8,163 8,380 6,816
Comprehensive income attributable to Parent                 8,135 8,178 6,883
Elimination and Consolidation Adjustments [Member]                      
Service revenue                 0 0 0
Management fee revenue                 (1,982) (1,868) (1,771)
Revenue                 (1,982) (1,868) (1,771)
Costs and Expenses:                      
Programming and production                 0 0 0
Other operating and administrative                 (1,982) (1,868) (1,771)
Advertising, marketing and promotion                 0 0 0
Depreciation                 0 0 0
Amortization                 0 0 0
Costs and expenses, total                 (1,982) (1,868) (1,771)
Operating income (loss)                 0 0 0
Other Income (Expense):                      
Interest expense                 0 0 0
Investment income (loss), net                 0 0 0
Equity in net income (losses) of investees, net                 (34,116) (34,161) (27,860)
Other income (expense), net                 0 0 0
Nonoperating income (Expense), Total                 (34,116) (34,161) (27,860)
Income (loss) before income taxes                 (34,116) (34,161) (27,860)
Income tax (expense) benefit                 0 0 0
Net income (loss)                 (34,116) (34,161) (27,860)
Net (income) loss attributable to noncontrolling interests and redeemable subsidiary preferred stock                 0 0 0
Net income (loss) attributable to Parent                 (34,116) (34,161) (27,860)
Comprehensive income attributable to Parent                 (34,042) (33,922) (27,784)
Comcast Parent [Member]                      
Service revenue                 0 0 0
Management fee revenue                 1,005 947 897
Revenue                 1,005 947 897
Costs and Expenses:                      
Programming and production                 0 0 0
Other operating and administrative                 760 751 403
Advertising, marketing and promotion                 0 0 0
Depreciation                 31 34 30
Amortization                 6 6 5
Costs and expenses, total                 797 791 438
Operating income (loss)                 208 156 459
Other Income (Expense):                      
Interest expense                 (1,744) (1,621) (1,523)
Investment income (loss), net                 6 3 0
Equity in net income (losses) of investees, net                 9,159 9,330 7,509
Other income (expense), net                 (3) 0 (2)
Nonoperating income (Expense), Total                 7,418 7,712 5,984
Income (loss) before income taxes                 7,626 7,868 6,443
Income tax (expense) benefit                 537 512 373
Net income (loss)                 8,163 8,380 6,816
Net (income) loss attributable to noncontrolling interests and redeemable subsidiary preferred stock                 0 0 0
Net income (loss) attributable to Parent                 8,163 8,380 6,816
Comprehensive income attributable to Parent                 8,135 8,178 6,883
Comcast Holdings [Member]                      
Service revenue                 0 0 0
Management fee revenue                 0 0 0
Revenue                 0 0 0
Costs and Expenses:                      
Programming and production                 0 0 0
Other operating and administrative                 0 0 0
Advertising, marketing and promotion                 0 0 0
Depreciation                 0 0 0
Amortization                 0 0 0
Costs and expenses, total                 0 0 0
Operating income (loss)                 0 0 0
Other Income (Expense):                      
Interest expense                 (12) (11) (11)
Investment income (loss), net                 (1) 12 (13)
Equity in net income (losses) of investees, net                 8,651 8,843 7,540
Other income (expense), net                 0 0 0
Nonoperating income (Expense), Total                 8,638 8,844 7,516
Income (loss) before income taxes                 8,638 8,844 7,516
Income tax (expense) benefit                 4 0 9
Net income (loss)                 8,642 8,844 7,525
Net (income) loss attributable to noncontrolling interests and redeemable subsidiary preferred stock                 0 0 0
Net income (loss) attributable to Parent                 8,642 8,844 7,525
Comprehensive income attributable to Parent                 8,625 8,807 7,521
CCCL Parent [Member]                      
Service revenue                 0 0 0
Management fee revenue                 977 921 874
Revenue                 977 921 874
Costs and Expenses:                      
Programming and production                 0 0 0
Other operating and administrative                 977 921 874
Advertising, marketing and promotion                 0 0 0
Depreciation                 0 0 0
Amortization                 0 0 0
Costs and expenses, total                 977 921 874
Operating income (loss)                 0 0 0
Other Income (Expense):                      
Interest expense                 (270) (294) (338)
Investment income (loss), net                 0 0 0
Equity in net income (losses) of investees, net                 8,040 8,350 7,512
Other income (expense), net                 0 0 2
Nonoperating income (Expense), Total                 7,770 8,056 7,176
Income (loss) before income taxes                 7,770 8,056 7,176
Income tax (expense) benefit                 94 103 117
Net income (loss)                 7,864 8,159 7,293
Net (income) loss attributable to noncontrolling interests and redeemable subsidiary preferred stock                 0 0 0
Net income (loss) attributable to Parent                 7,864 8,159 7,293
Comprehensive income attributable to Parent                 7,864 8,163 7,277
NBCUniversal Media Parent [Member]                      
Service revenue                 0 0 0
Management fee revenue                 0 0 0
Revenue                 0 0 0
Costs and Expenses:                      
Programming and production                 0 0 0
Other operating and administrative                 922 908 855
Advertising, marketing and promotion                 0 0 0
Depreciation                 0 0 0
Amortization                 0 0 0
Costs and expenses, total                 922 908 855
Operating income (loss)                 (922) (908) (855)
Other Income (Expense):                      
Interest expense                 (462) (479) (488)
Investment income (loss), net                 (19) (7) 3
Equity in net income (losses) of investees, net                 4,852 4,523 3,331
Other income (expense), net                 (31) (4) (1)
Nonoperating income (Expense), Total                 4,340 4,033 2,845
Income (loss) before income taxes                 3,418 3,125 1,990
Income tax (expense) benefit                 (4) (10) (22)
Net income (loss)                 3,414 3,115 1,968
Net (income) loss attributable to noncontrolling interests and redeemable subsidiary preferred stock                 0 0 0
Net income (loss) attributable to Parent                 3,414 3,115 1,968
Comprehensive income attributable to Parent                 3,361 2,972 2,017
Comcast Non-Guarantor Subsidiaries [Member]                      
Service revenue                 74,510 68,775 64,657
Management fee revenue                 0 0 0
Revenue                 74,510 68,775 64,657
Costs and Expenses:                      
Programming and production                 22,550 20,912 19,670
Other operating and administrative                 20,662 19,142 18,214
Advertising, marketing and promotion                 5,943 5,086 4,978
Depreciation                 6,750 6,303 6,224
Amortization                 1,893 1,676 1,612
Costs and expenses, total                 57,798 53,119 50,698
Operating income (loss)                 16,712 15,656 13,959
Other Income (Expense):                      
Interest expense                 (214) (212) (214)
Investment income (loss), net                 95 288 586
Equity in net income (losses) of investees, net                 3,089 3,212 1,882
Other income (expense), net                 354 (211) (363)
Nonoperating income (Expense), Total                 3,324 3,077 1,891
Income (loss) before income taxes                 20,036 18,733 15,850
Income tax (expense) benefit                 (5,590) (4,478) (4,457)
Net income (loss)                 14,446 14,255 11,393
Net (income) loss attributable to noncontrolling interests and redeemable subsidiary preferred stock                 (250) (212) (319)
Net income (loss) attributable to Parent                 14,196 14,043 11,074
Comprehensive income attributable to Parent                 $ 14,192 $ 13,980 $ 10,969