Consolidated Statement of Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue	$ 108,942	$ 94,507	$ 85,029
Costs and Expenses:
Programming and production	34,440	29,692	25,355
Other operating and administrative	32,807	28,094	25,449
Advertising, marketing and promotion	7,617	7,036	6,519
Depreciation	8,663	8,281	7,914
Amortization	4,290	2,736	2,216
Other operating gains	0	(341)	(442)
Total costs and expenses	87,817	75,498	67,011
Operating income (loss)	21,125	19,009	18,018
Interest expense	(4,567)	(3,542)	(3,086)
Investment and other income (loss), net	438	(225)	421
Income (loss) before income taxes	16,996	15,242	15,353
Income tax (expense) benefit	(3,673)	(3,380)	7,569
Net income	13,323	11,862	22,922
Less: Net income attributable to noncontrolling interests and redeemable subsidiary preferred stock	266	131	187
Net income attributable to Comcast Corporation	$ 13,057	$ 11,731	$ 22,735
Basic earnings per common share attributable to Comcast Corporation shareholders (in dollars per share)	$ 2.87	$ 2.56	$ 4.83
Diluted earnings per common share attributable to Comcast Corporation shareholders (in dollars per share)	$ 2.83	$ 2.53	$ 4.75
NBCUniversal Media LLC [Member]
Revenue	$ 34,021	$ 35,895	$ 32,950
Costs and Expenses:
Programming and production	14,462	16,330	14,276
Other operating and administrative	8,123	7,980	7,687
Advertising, marketing and promotion	2,681	2,952	2,806
Depreciation	1,023	1,001	994
Amortization	1,106	1,107	1,047
Other operating gains	0	(141)	(337)
Total costs and expenses	27,395	29,229	26,473
Operating income (loss)	6,626	6,666	6,477
Interest expense	(738)	(489)	(727)
Investment and other income (loss), net	396	(521)	(144)
Income (loss) before income taxes	6,284	5,656	5,606
Income tax (expense) benefit	(320)	(351)	(392)
Net income	5,964	5,305	5,214
Less: Net income attributable to noncontrolling interests	180	68	134
Net income attributable to Comcast Corporation	$ 5,784	$ 5,237	$ 5,080