Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentDescriptionOfVariableRateBasis
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- 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_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of debt issuance costs (for example, but not limited to, legal, accounting, broker, and regulatory fees).

+ References

No definition available.

+ Details

Name:	us-gaap_DebtIssuanceCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_LongTermDebtOtherDisclosuresAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.17)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_UnamortizedDebtIssuanceExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cog_AccordionFeatureAmendedFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_BaseRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	cog_DebtInstrumentLeverageRatioAxis=cog_DebtInstrumentLeverageRatioLessThan1.0xMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	cog_DebtInstrumentLeverageRatioAxis=cog_DebtInstrumentDebtLeverageRatioGreaterThanOrEqualTo1.0xButLessThan2.0xMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	cog_DebtInstrumentLeverageRatioAxis=cog_DebtInstrumentLeverageRatioGreaterThanOrEqualTo2.0xButLessThan3.0xMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	cog_DebtInstrumentLeverageRatioAxis=cog_DebtInstrumentLeverageRatioGreaterThanOrEqualTo3.0xMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Debt and Credit Agreements (Details 3) - Revolving credit facility - USD ($)	Apr. 17, 2015	Apr. 16, 2015
Debt Instrument [Line Items]
Borrowing base	$ 3,400,000,000.0	$ 3,100,000,000.0
Current borrowing capacity	1,800,000,000	$ 1,400,000,000
Debt issuance cost	7,800,000
Unamortized costs	8,300,000
Accordion Feature, Amended Facility
Debt Instrument [Line Items]
Borrowing base	$ 500,000,000
Minimum
Debt Instrument [Line Items]
Commitment fee on the unused available balance	0.30%
Maximum
Debt Instrument [Line Items]
Commitment fee on the unused available balance	0.50%
Eurodollar LIBOR
Debt Instrument [Line Items]
Description of variable rate basis	Eurodollar (LIBOR)
Alternate base rate (ABR)
Debt Instrument [Line Items]
Description of variable rate basis	alternate base rate (ABR)
Debt Instrument Leverage Ratio Less than 1.0x \| Eurodollar LIBOR
Interest Rates Under Amended Credit Facility
Basis spread on variable rate	1.50%
Debt Instrument Leverage Ratio Less than 1.0x \| Alternate base rate (ABR)
Interest Rates Under Amended Credit Facility
Basis spread on variable rate	0.50%
Debt Instrument Leverage Ratio Greater than or Equal to 1.0x but Less than 2.0x \| Eurodollar LIBOR
Interest Rates Under Amended Credit Facility
Basis spread on variable rate	1.75%
Debt Instrument Leverage Ratio Greater than or Equal to 1.0x but Less than 2.0x \| Alternate base rate (ABR)
Interest Rates Under Amended Credit Facility
Basis spread on variable rate	0.75%
Debt Instrument Leverage Ratio Greater than or Equal to 2.0x but Less 3.0x \| Eurodollar LIBOR
Interest Rates Under Amended Credit Facility
Basis spread on variable rate	2.00%
Debt Instrument Leverage Ratio Greater than or Equal to 2.0x but Less 3.0x \| Alternate base rate (ABR)
Interest Rates Under Amended Credit Facility
Basis spread on variable rate	1.00%
Debt Instrument Leverage Ratio Greater than or Equal to 3.0x \| Eurodollar LIBOR
Interest Rates Under Amended Credit Facility
Basis spread on variable rate	2.25%
Debt Instrument Leverage Ratio Greater than or Equal to 3.0x \| Alternate base rate (ABR)
Interest Rates Under Amended Credit Facility
Basis spread on variable rate	1.25%