Fair Value (Details 1) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Other financing obligations	$ 171	$ 173
Other financing obligations, Current	$ 5	$ 6

Including both current and noncurrent portions, carrying amount as of the balance sheet date of other forms of debt not elsewhere specified in the taxonomy with initial maturities beyond one year or beyond the normal operating cycle, if longer.

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 19, 20, 22

-Article 5

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

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