Asset Retirement Obligations (Notes)

12 Months Ended

Dec. 31, 2014

Asset Retirement Obligation Disclosure [Abstract]

Asset Retirement Obligations

ASSET RETIREMENT OBLIGATIONS

Our accrued asset retirement obligations relate to our gas storage and transmission facilities. At the end of the useful life of our facilities, we are legally obligated to remove certain transmission facilities including underground pipelines, major river spans, compressor stations and meter station facilities. These obligations also include restoration of the property sites after removal of the facilities from above and below the ground.

During 2014 and 2013, our overall asset retirement obligation changed as follows (in thousands):

	2014			2013
Beginning balance	$	60,753		$	67,640
Accretion	5,602			5,708
New obligations	157			51
Changes in estimates of existing obligations (1)	28,171			(12,577		)
Property Dispositions & Settlements	(5		)	(69		)
Ending balance	$	94,678		$	60,753

(1) Changes in estimates of existing obligations are primarily due to the annual review process, which considers various factors including inflation rates, current estimates for removal cost, discount rates, and the estimated remaining life of assets. The increase in 2014 is primarily attributed to increases in current estimates for removal costs and inflation rate, and a decrease in the discount rate. The decrease in 2013 is primarily attributed to increases in the discount rate and the remaining life of the applicable property.