v2.4.0.6

COMMITMENTS AND CONTINGENCIES Narrative (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
Loss Contingencies [Line Items]
Loss Contingency Accrual, at Carrying Value	$ 43.6
Grace Energy Corporation Matter [Member]
Loss Contingencies [Line Items]
Court Judgment, Remediation Costs Not Recoverable by Plaintiff	3.5
Court Judgment, Attorney Costs Awarded to Plaintiff	1.8
Deptartment of Justice Estimated Remediation Expenses	71.9
Loss Contingencies, Estimated Settlement Payment	$ 11.7

X

- Definition

Attorney costs awarded to plaintiff, per a court judgment

+ References

No definition available.

+ Details

Name:	ns_CourtJudgmentAttorneyCostsAwardedToPlaintiff
Namespace Prefix:	ns_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Remediation costs not recoverable by plaintiff, per a court judgment.

+ References

No definition available.

+ Details

Name:	ns_CourtJudgmentRemediationCostsNotRecoverableByPlaintiff
Namespace Prefix:	ns_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Department of Justice past and future estimated remediation expenses.

+ References

No definition available.

+ Details

Name:	ns_DeptartmentOfJusticeEstimatedRemediationExpenses
Namespace Prefix:	ns_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The estimated amount an entity will pay in a settlement agreement to resolve the legal matter.

+ References

No definition available.

+ Details

Name:	ns_LossContingenciesEstimatedSettlementPayment
Namespace Prefix:	ns_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

X

- Details

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

X

- Definition

The carrying amount as of the balance sheet date of the combined total of loss contingency liabilities.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 5

-Paragraph 9, 10, 11, 12

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14326-108349

+ Details

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