Commitments and Contingencies (Details) (Transportation and Gathering Agreements, USD $) In Millions, unless otherwise specified	9 Months Ended
Sep. 30, 2014
Transportation and Gathering Agreements
Commitments and Contingencies
Amount of increase in the future aggregate obligations under the transportation commitments	$ 230.5
Period over which increase in transportation and gathering agreements obligation is affected	13 years

The period affected by the increase or (decrease) in aggregate future transportation agreement obligations.

No definition available.

Name:	cog_PeriodOverWhichIncreaseDecreaseInAggregateFutureTransportationAgreementObligationIsAffected
Namespace Prefix:	cog_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration