Benefit Plans, Additional Disclosures (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Estimated cash contributions to benefit plans next year [Abstract]
Percentage of compensation eligible for the Company match (in hundredths)	0.06
Cash contributions made by the company to 401(k) plans	$ 14	$ 11	$ 9
Rabbi trust assets [Abstract]
Mutual fund investments	82	96
Noble Energy common stock (at fair value)	80	82
Total Rabbi trust assets	162	178
Liability under related deferred compensation plan	162	178
Number of shares of Noble Energy common stock held by Rabbi trust (in shares)	848,940	949,040
Shares of company common stock held in the rabbi trust attributable to a member of the Board of Directors (in shares)	800,000
Percentage of company common stock held in the rabbi trust attributable to a member of the Board of Directors (in hundredths)	94.00%
Shares of company common stock received by rabbi trust participants (in shares)	100,000	100,000
Shares of company common stock sold by rabbi trust participants (in shares)	100	100	1,892
Distributions to rabbi trust participants	17	17	0
Deferred compensation expense (income) recognized	8	15	23
Deferred compensation liabilities outstanding under the unfunded plan	60	51	45
Shares of common stock held by the rabbi trust (in dollars per share)	$ 33.44
Retirement and restoration plans [Member]
Estimated cash contributions to benefit plans next year [Abstract]
Expected cash contributions to the plan in 2012	13
2012	21
2013	23
2014	25
2015	24
2016	26
Years 2017 to 2020	141
Medical and life plans [Member]
Estimated cash contributions to benefit plans next year [Abstract]
Expected cash contributions to the plan in 2012	1
2012	1
2013	1
2014	1
2015	2
2016	2
Years 2017 to 2020	11
Unfunded restoration plan [Member]
Estimated cash contributions to benefit plans next year [Abstract]
Expected cash contributions to the plan in 2012	$ 3

Deferred compensation expense (income) recognized during the reporting period.

No definition available.

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- Definition

Number of shares of company stock held in the rabbi trust attributable to a member of the board of directors.

+ References

No definition available.

+ Details

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- Definition

Percentage of shares of company stock held in the rabbi trust attributable to a member of the board of directors.

+ References

No definition available.

+ Details

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- Definition

Mutual fund investments held in a rabbi trust. These mutual funds may include equities, money market instruments, and other types of investments.

+ References

No definition available.

+ Details

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- Definition

The amount of distributions to rabbi trust participants.

+ References

No definition available.

+ Details

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- Definition

The number of company shares received by plan participants in the rabbi trust.

+ References

No definition available.

+ Details

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- Definition

The number of company shares sold by plan participants in the rabbi trust.

+ References

No definition available.

+ Details

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- Definition

Price per share of common stock held in a trust that has been set up specifically to accumulate stock for the sole purpose of distribution to participating employees but not yet earned.

+ References

No definition available.

+ Details

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- Definition

Value of common stock issued to a trust (for example, a 'rabbi trust') set up specifically to accumulate stock for the sole purpose of distribution to participating employees. This trust does not allow employees to immediately or after a holding period diversify into nonemployer securities. The deferred compensation plan for which this trust is set up must be settled by the delivery of a fixed number of shares of employer stock.

+ References

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

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 97-14

+ Details

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- Definition

Number of common stock held in a trust that has been set up specifically to accumulate stock for the sole purpose of distribution to participating employees but not yet earned.

+ References

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

-Publisher AICPA

-Name Statement of Position (SOP)

-Number 93-6

-Paragraph 14

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- Definition

Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements. Represents currently earned compensation under compensation arrangements that is not actually paid until a later date.

+ References

No definition available.

+ Details

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- Definition

Carrying amount as of the balance sheet date of assets held under deferred compensation agreements.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 17

-Article 5

+ Details

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- Definition

The employer's best estimate, as soon as it can be reasonably determined, of contributions expected to be paid to the plan during the next fiscal year beginning after the date of the latest statement of financial position. Estimated contributions may be presented in the aggregate combining (1) contributions required by funding regulations or laws, (2) discretionary contributions, and (3) noncash contributions.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph g

+ Details

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- Definition

The amount of the aggregate benefits expected to be paid in the five fiscal years thereafter (the aggregate amount of benefits expected to be paid in years 6 through 10 after the date of the latest statement of financial position).

+ References