v2.4.0.6

Condensed Consolidating Financial Information (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Jun. 30, 2012
Holding company ownership in subsidiaries	100.00%
Comcast Holdings' ZONES due October 2029 [Member]
Amount of unconditional guarantee of principal amount outstanding of Comcast Holdings	185
Debt Instrument, Maturity Date, Description	2029
Comcast Holdings' 10 5/8% senior subordinated debentures due 2012 [Member]
Current principal balance	202
Interest rate	10.625%
Debt Instrument, Maturity Date, Description	2012
Comcast Holdings' ZONES due November 2029 [Member]
Current principal balance	62
Debt Instrument, Maturity Date, Description	2029

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- Definition

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-Name Statement of Financial Accounting Standard (FAS)

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