Transactions with Major Customers and Affiliates (Tables)

12 Months Ended

Dec. 31, 2013

Transactions with Major Customers and Affiliates [Abstract]

Schedule of revenue by major customers

During the periods presented, more than 10 percent of our operating revenues were generated from each of the following customers:

	Years Ended December 31,
	2013		2012		2011
	(Thousands of Dollars)
Puget Sound Energy, Inc.	$	110,111	$	100,799	$	99,116
Northwest Natural Gas Company	51,085		47,297		47,322