General	6 Months Ended
General	Jun. 30, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
General	General Organization We are a Delaware limited liability company, originally formed in 1927 as a corporation. We are an interstate pipeline system serving the Rocky Mountain Region. Unless the context otherwise requires, references to "us," we," "our," or "CIG," are describing Colorado Interstate Gas Company, L.L.C. and its consolidated subsidiaries. We are wholly owned by El Paso Pipeline Partners Operating Company, L.L.C., a wholly owned subsidiary of El Paso Pipeline Partners (EPB), a master limited partnership of El Paso LLC (El Paso), a wholly owned subsidiary of Kinder Morgan, Inc. (KMI). On May 24, 2012, EPB acquired the remaining 14% interest in us from a wholly owned subsidiary of El Paso, and we became an indirect wholly owned subsidiary of EPB. Basis of Presentation We have prepared our accompanying unaudited consolidated financial statements under the rules and regulations of the United States Securities and Exchange Commission (SEC). These rules and regulations conform to the accounting principles contained in the Financial Accounting Standards Board's Accounting Standards Codification, the single source of Generally Accepted Accounting Principles in the United States of America (GAAP) and referred to in this report as the Codification. Under such rules and regulations, we have condensed or omitted certain information and notes normally included in financial statements prepared in conformity with the Codification. We believe, however, that our disclosures are adequate to make the information presented not misleading. Our accompanying consolidated financial statements reflect normal adjustments, and also recurring adjustments that are, in the opinion of our management, necessary for a fair presentation of our financial results for the interim periods. Certain amounts from prior periods have been reclassified to conform to the current presentation. Interim results are not necessarily indicative of results for a full year; accordingly, you should read these consolidated financial statements in conjunction with our consolidated financial statements and related notes included in our Annual Report on Form 10-K for the year ended December 31, 2012, which we refer to in this report as our 2012 Form 10-K. Immaterial Correction During the second quarter of 2012, we determined that certain accrued environmental liabilities established in periods prior to 2008 were overstated by approximately $6 million. We corrected this error in June 2012 by reducing accrued liabilities by approximately $6 million, with an offsetting reduction in operating expenses. We evaluated the impact of the error and determined that it was not material to our previously reported consolidated financial statements. Additionally, we determined that the correction of the error was not material to our 2012 consolidated financial statements.

The entire disclosure for organization, consolidation and basis of presentation of financial statements disclosure.

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

-Publisher FASB

-Name FASB Interpretation (FIN)

-Number 46R

-Paragraph 4, 14, 15

-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 275

-SubTopic 10

-URI http://asc.fasb.org/subtopic&trid=2134480

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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS140-4/FIN46(R)-8

-Paragraph 8, C1, C7

-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 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 10

-URI http://asc.fasb.org/subtopic&trid=2122150

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 720

-SubTopic 15

-URI http://asc.fasb.org/subtopic&trid=2122524

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=7880789&loc=SL6228881-111685

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6359566&loc=d3e326-107755

Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6367646&loc=d3e18780-107790

Reference 9: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 10

-Section 45

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=7668296&loc=d3e288-107754

Reference 10: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-URI http://asc.fasb.org/subtopic&trid=2197480

Reference 11: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=18733093&loc=d3e5614-111684

Reference 12: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 51

-Paragraph 2-6

-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 13: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 915

-SubTopic 235

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6472506&loc=d3e38932-110933

Reference 14: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 852

-SubTopic 10

-URI http://asc.fasb.org/subtopic&trid=2209116

Reference 15: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 272

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70478-108055

Reference 16: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Statement of Position (SOP)

-Number 94-6

-Paragraph 10

-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.

+ Details

COLORADO INTERSTATE GAS COMPANY, L.L.C. 10-Q