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Largest individual loan commitment percent of total loan commitments by any one lender for revolving credit facility.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Percentage added to the prime rate based upon a grid of our debt rating in determining the interest rate on borrowings under our credit facility (one of two options).

+ References

No definition available.

+ Details

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- Definition

Percentage added to LIBOR based upon a grid of our debt rating to determine the interest rate on borrowings under our credit facility (one of two options).

+ References

No definition available.

+ Details

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- Definition

Percentage based on a grid of our debt rating on which letters of credit fees are based.

+ References

No definition available.

+ Details

Name:	nfx_PercentageOnWhichAnnualFeesOnGridOfDebtRatingAreSubject
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- Definition

Percentage on which issuance fees on Letter of credit are subject

+ References

No definition available.

+ Details

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Namespace Prefix:	nfx_
Data Type:	num:percentItemType
Balance Type:	na
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- Definition

Ratio of total debt to earnings before gain or loss on disposition of assets, interest expense, income taxes and noncash items that must be maintained due to restrictive covenants on our credit facility.

+ References

No definition available.

+ Details

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

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

+ Details

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- Details

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- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 20, 22

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

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

- Definition

Amount of the fee for available but unused credit capacity under the credit 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

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

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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

+ Details

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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

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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

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ 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 210.5-02.22)

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

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

+ Details

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Balance Type:	credit
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- Definition

Indebtedness divided by net capital.

+ References

No definition available.

+ Details

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Debt (Details) (USD $)	3 Months Ended		9 Months Ended
Debt (Details) (USD $)	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Debt Instrument [Line Items]
Line of Credit Facility, Amount Outstanding	$ 0		$ 0		$ 649,000,000
Long-term debt	(3,046,000,000)		(3,046,000,000)		(3,694,000,000)
Debt (Textuals)
Line of Credit Facility, Maximum Borrowing Capacity	1,400,000,000		1,400,000,000
Largest individual loan commitment by any lender of total commitments	14.00%		14.00%
Commitment fees incurred	1,000,000	1,000,000	3,000,000	3,000,000
Ratio of Indebtedness to Net Capital 1	0.6		0.6
Ratio of total debt to earnings before gain or loss on disposition of assets, interest expense, income taxes and noncash items	3.0		3.0
Line of Credit Facility, Current Borrowing Capacity	195,000,000		195,000,000
Percentage of basis points to be added for calculation of interest rate			0.50%
Percent added to prime rate based on grid of our debt rating			0.75%
Percentage added to LIBOR based on grid of our debt rating			1.75%
Commitment fee percentage on unused capacity of line of credit			0.30%
Issuance fees percentage on letter of credit			0.20%
Percentage based on a grid of our debt rating on which letters of credit fees are based.			1.75%
Revolving credit facility - LIBOR based loans
Debt Instrument [Line Items]
Line of Credit Facility, Amount Outstanding	0		0		585,000,000
Money market lines of credit(1)
Debt Instrument [Line Items]
Line of Credit Facility, Amount Outstanding	0		0		64,000,000
5.75% Senior Notes Due 2022 [Member]
Debt Instrument [Line Items]
Long-term debt	(750,000,000)		(750,000,000)		(750,000,000)
Debt Instrument, Interest Rate, Stated Percentage	5.75%		5.75%		5.75%
5.625% Senior Notes Due 2024 [Member]
Debt Instrument [Line Items]
Long-term debt	(1,000,000,000)		(1,000,000,000)		(1,000,000,000)
Debt Instrument, Interest Rate, Stated Percentage	5.625%		5.625%		5.625%
Total senior unsecured debt
Debt Instrument [Line Items]
Long-term debt	(1,750,000,000)		(1,750,000,000)		(2,399,000,000)
7.125% Senior Subordinated Notes due 2018 [Member]
Debt Instrument [Line Items]
Long-term debt	(600,000,000)		(600,000,000)		(600,000,000)
Debt Instrument, Interest Rate, Stated Percentage	7.125%		7.125%		7.125%
6.875% Senior Subordinated Notes due 2020 [Member]
Debt Instrument [Line Items]
Long-term debt	(700,000,000)		(700,000,000)		(700,000,000)
Debt Instrument, Interest Rate, Stated Percentage	6.875%		6.875%		6.875%
Discount on notes [Member]
Debt Instrument [Line Items]
Long-term debt	$ 4,000,000		$ 4,000,000		$ 5,000,000