Consolidated Statement of Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Revenue	$ 116,385	$ 103,564	$ 108,942
Costs and Expenses:
Programming and production	38,450	33,121	34,440
Other operating and administrative	35,619	33,109	32,807
Advertising, marketing and promotion	7,695	6,741	7,617
Depreciation	8,628	8,320	8,663
Amortization	5,176	4,780	4,290
Total costs and expenses	95,568	86,071	87,817
Operating income	20,817	17,493	21,125
Interest expense	(4,281)	(4,588)	(4,567)
Investment and other income (loss), net	2,557	1,160	438
Income before income taxes	19,093	14,065	16,996
Income tax expense	(5,259)	(3,364)	(3,673)
Net income	13,833	10,701	13,323
Less: Net income (loss) attributable to noncontrolling interests and redeemable subsidiary preferred stock	(325)	167	266
Net income attributable to Comcast Corporation	$ 14,159	$ 10,534	$ 13,057
Basic earnings per common share attributable to Comcast Corporation shareholders (in dollars per share)	$ 3.09	$ 2.30	$ 2.87
Diluted earnings per common share attributable to Comcast Corporation shareholders (in dollars per share)	$ 3.04	$ 2.28	$ 2.83