Asset retirement obligations

12 Months Ended

Dec. 31, 2020

Asset Retirement Obligation [Abstract]

Asset retirement obligations

Asset Retirement Obligations

The Company records obligations related to retirement costs of natural gas distribution mains and lines, natural gas transmission lines, natural gas storage wells, decommissioning of certain electric generating facilities, reclamation of certain aggregate properties, special handling and disposal of hazardous materials at certain electric generating facilities, natural gas distribution facilities and buildings, and certain other obligations as asset retirement obligations.

A reconciliation of the Company's liability, which the current portion is included in other accrued liabilities on the Consolidated Balance Sheets, for the years ended December 31 was as follows:

	2020		2019
	(In thousands)
Balance at beginning of year	$	417,575	$	375,553
Liabilities incurred	11,560		25,869
Liabilities acquired	1,378		486
Liabilities settled	(5,369)		(7,097)
Accretion expense*	21,668		19,789
Revisions in estimates	107		2,975
Balance at end of year	$	446,919	$	417,575

*    Includes $20.1 million and $18.3 million in 2020 and 2019, respectively, related to regulatory assets.

The Company believes that largely all expenses related to asset retirement obligations at the Company's regulated operations will be recovered in rates over time and, accordingly, defers such expenses as regulatory assets. For more information on the Company's regulatory assets and liabilities, see Note 6.