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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

Name:	nfx_PercentAddedToPrimeRateBasedOnGridOfOurDebtRating
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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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Balance Type:	na
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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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Data Type:	num:percentItemType
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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

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

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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

- Definition

Amount borrowed under the credit facility as of the balance sheet date.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

Name:	us-gaap_LineOfCreditFacilityAmountOutstanding
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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

Name:	us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity
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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

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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
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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 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)

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

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash inflow from additional borrowings, net of cash paid to third parties in connection with debt origination.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Indebtedness divided by net capital.

+ References

No definition available.

+ Details

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Debt (Details) (USD $)	12 Months Ended
Debt (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Mar. 31, 2013
Debt Instrument [Line Items]
Line of Credit Facility, Amount Outstanding	$ 649,000,000	$ 0
Long-term debt	3,694,000,000	3,045,000,000
Debt issuance costs	4,000,000
Net proceeds from issuance of Senior Notes		990,000,000
Debt (Textuals)
Line of Credit Facility, Maximum Borrowing Capacity	1,400,000,000			1,250,000,000
Largest individual loan commitment by any lender of total commitments	14.00%
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%
Commitment fees incurred	3,000,000	3,000,000	2,000,000
Ratio of Indebtedness to Net Capital 1	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
Letters of Credit Outstanding, Amount	58,000,000
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%
Line of Credit Facility, Current Borrowing Capacity	96,000,000
Discount On Notes [Member]
Debt Instrument [Line Items]
Long-term debt	(5,000,000)	(5,000,000)
6.875% Senior Subordinated Notes due 2020 [Member]
Debt Instrument [Line Items]
Long-term debt	700,000,000	700,000,000
Debt Instrument, Interest Rate, Stated Percentage	6.875%	6.875%
7.125% Senior Subordinated Notes due 2018 [Member]
Debt Instrument [Line Items]
Long-term debt	600,000,000	600,000,000
Debt Instrument, Interest Rate, Stated Percentage	7.125%	7.125%
Total senior unsecured debt
Debt Instrument [Line Items]
Long-term debt	1,750,000,000	1,750,000,000
5.625% Senior Notes Due 2024 [Member]
Debt Instrument [Line Items]
Long-term debt	1,000,000,000	1,000,000,000
Debt Instrument, Interest Rate, Stated Percentage	5.625%	5.625%
5.75 %Senior Notes Due 2022 [Member]
Debt Instrument [Line Items]
Long-term debt	750,000,000	750,000,000
Debt Instrument, Interest Rate, Stated Percentage	5.75%	5.75%
Money market lines of credit [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Amount Outstanding	64,000,000	0
Revolving Credit Facility Libor Based Loans [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Amount Outstanding	$ 585,000,000	$ 0