Rate and Regulatory Matters (Notes)	12 Months Ended
Dec. 31, 2013
Public Utilities, Rate Matters [Abstract]
Rate and Regulatory Matters	RATE AND REGULATORY MATTERSRate Case Settlement FilingOn April 26, 2012, the FERC unconditionally approved Northwest’s Stipulation and Settlement Agreement (Settlement) filed on March 15, 2012. The Settlement specified an annual cost of service of $466.5 million and established a new general system firm transportation rate of $0.44 per dekatherm, a 7.4 percent increase over the previous rate. New rates became effective January 1, 2013, and will remain in effect for a minimum of 3 years and a maximum of 5 years.

Describes all of the specific events that have or may impact rates and amortization of regulatory assets and liabilities (for example, pending or recently concluded regulatory proceedings, environmental requirements). Specifics may include quantifications related to rates, costs, and earnings. Events may relate to rate moratoriums or price caps.

No definition available.

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