Asset Retirement Obligations (Notes)

12 Months Ended

Dec. 31, 2020

Asset Retirement Obligation Disclosure [Abstract]

ASSET RETIREMENT OBLIGATIONS

These accrued obligations relate to underground storage caverns, offshore platforms, pipelines, and gas transmission facilities. At the end of the useful life of each respective asset, we are legally obligated to plug storage caverns and remove any related surface equipment, to dismantle offshore platforms, to cap certain gathering pipelines at the wellhead connection and remove any related surface equipment, and to remove certain components of gas transmission facilities from the ground.

During 2020 and 2019, our overall asset retirement obligation changed as follows (in thousands):


	2020		2019
Beginning balance	$	459,209	$	394,323
Accretion	23,142		21,806
New obligations	1,154		103
Changes in estimates of existing obligations (1)	(21,889)		49,070
Property dispositions/obligations settled	(11,115)		(6,093)
Ending balance	$	450,501	$	459,209

(1) Changes in estimates of existing obligations are primarily due to the annual review process, which considers various factors including inflation rate, current estimates for removal costs, discount rates, and the estimated remaining life of assets. The decrease in 2020 is primarily due to a decrease in the inflation rate. The increase in 2019 is primarily due to an increase in the inflation rate and a decrease in the discount rate.

We are entitled to collect in rates the amounts necessary to fund our ARO. All funds received for such retirements are deposited into an external trust account dedicated to funding our ARO (See Note 6).