Programming and Production Costs - Schedule of Recognized Programming and Production Costs (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Other Industries [Abstract]
Video distribution programming	$ 2,265	$ 2,467	$ 6,987	$ 7,637
Film and television content:
Owned	2,269	2,551	7,435	7,438
Licensed, including sports rights	2,554	3,262	11,205	8,540
Other	427	375	1,161	1,031
Total programming and production costs	7,515	8,655	26,789	24,646
Amortization of owned film and television costs	$ 1,600	$ 2,000	$ 5,500	$ 6,000

The amount of expense recognized in the period for costs associated with video programming and content acquisition and production costs. Programming expenses include the fees paid to license the programming distributed to video customers, such as the programming license fees charged by cable networks and fees charged for retransmission of the signals from local broadcast television stations. Production costs include the amortization of owned and acquired programming, sports rights, direct production costs, residual and participation payments, production overhead, costs associated with the distribution of programming to third-party networks and other distribution platforms, and on-air talent costs. It also includes the amortization of capitalized theatrical film production and acquisition costs and distribution expenses.

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Namespace Prefix:	cmcsa_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration