XML 39 R26.htm IDEA: XBRL DOCUMENT v3.20.2
Asset Retirement Obligations
 9 Months Ended
Sep. 30, 2020
Asset Retirement Obligation Disclosure [Abstract]  
Asset Retirement Obligations Asset Retirement Obligations
During the nine months ended September 30, 2020, the Company revised its cost estimates for existing AROs at Cholla relating to updated estimates for the closure of ponds and facilities, and at Four Corners and Navajo Plant relating to corrective action and water monitoring costs (see additional details in Notes 4 and 8).

The following schedule shows the change in our asset retirement obligations for the nine months ended September 30, 2020 (dollars in thousands): 
 2020
Asset retirement obligations at January 1, 2020$657,218 
Changes attributable to: 
Accretion expense29,454 
Settlements(5,611)
Estimated cash flow revisions5,190 
Asset retirement obligations at September 30, 2020$686,251 

In accordance with regulatory accounting, APS accrues removal costs for its regulated utility assets, even if there is no legal obligation for removal.  See detail of regulatory liabilities in Note 4.