Condensed Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Net income	$ 3,203	$ 3,208	$ 6,835	$ 6,384
Unrealized gains (losses) on marketable securities, net of deferred taxes	1	(1)	2	(2)
Deferred gains (losses) on cash flow hedges, net of deferred taxes	123	(40)	64	(11)
Amounts reclassified to net income:
Realized (gains) losses on cash flow hedges, net of deferred taxes	(45)	46	13	26
Employee benefit obligations, net of deferred taxes	(9)	(8)	(16)	(16)
Currency translation adjustments, net of deferred taxes	(566)	(173)	241	(16)
Comprehensive income	2,707	3,032	7,139	6,365
Less: Net income (loss) attributable to noncontrolling interests and redeemable subsidiary preferred stock	78	(8)	157	50
Less: Other comprehensive income (loss) attributable to noncontrolling interests	(12)	(29)	(2)	(25)
Comprehensive income (loss) attributable to Comcast Corporation	2,641	3,069	6,984	6,340
NBCUniversal Media LLC [Member]
Net income	1,629	1,218	3,467	2,771
Deferred gains (losses) on cash flow hedges, net of deferred taxes	(2)	11	(3)	(2)
Amounts reclassified to net income:
Employee benefit obligations, net of deferred taxes	(3)	(3)	(5)	(7)
Currency translation adjustments, net of deferred taxes	66	(215)	47	(11)
Comprehensive income	1,690	1,011	3,506	2,751
Less: Net income (loss) attributable to noncontrolling interests	58	(29)	112	11
Less: Other comprehensive income (loss) attributable to noncontrolling interests	(12)	(29)	(2)	(25)
Comprehensive income (loss) attributable to Comcast Corporation	$ 1,644	$ 1,069	$ 3,396	$ 2,765