PROPERTIES AND EQUIPMENT, NET (Details 2)	3 Months Ended
Mar. 31, 2012 Y
PROPERTIES AND EQUIPMENT, NET
Minimum term of capitalization of exploratory well costs (in years)	1

Represents the term of capitalization used for aging disclosure.

No definition available.

Name:	cog_CapitalizedExploratoryWellCostsPeriodOfCapitalization
Namespace Prefix:	cog_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration