XML 38 R28.htm IDEA: XBRL DOCUMENT
v3.24.1.u1

Segment Information - Narrative (Details) | 3 Months Ended
--- | ---
Mar. 31, 2024 segment business
Segment Reporting Information [Line Items] |
Number of primary businesses | business | 2
Connectivity & Platforms |
Segment Reporting Information [Line Items] |
Number of reportable segments | 2
Content & Experiences |
Segment Reporting Information [Line Items] |
Number of reportable segments | 3

X
- Definition Number Of Businesses + References No definition available. + Details
Name: | cmcsa_NumberOfBusinesses
Namespace Prefix: | cmcsa_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 18 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482810/280-10-50-18 + Details
Name: | us-gaap_NumberOfReportableSegments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_SegmentReportingInformationLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | cmcsa_BusinessUnitAxis=cmcsa_ConnectivityAndPlatformsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | cmcsa_BusinessUnitAxis=cmcsa_ContentExperiencesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |