Programming and Production Costs - Programming and Production Expense (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Other Industries [Abstract]
Video distribution programming	$ 13,550	$ 12,684
Film and television content:
Owned	8,957	7,973
Licensed, including sports rights	14,733	11,264
Other	1,210	1,200
Total programming and production costs	38,450	33,121	$ 34,440
Amortization of owned film and television costs	$ 7,300	$ 6,600

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