ASSET RETIREMENT OBLIGATIONS

12 Months Ended

Dec. 31, 2016

Asset Retirement Obligation [Abstract]

ASSET RETIREMENT OBLIGATIONS

ASSET RETIREMENT OBLIGATIONS

AROs represent obligations that result from laws, statutes, contracts and regulations related to the eventual retirement of certain of Questar Gas' long-lived assets. Revisions to estimates result from material changes in the expected timing or amount of cash flows associated with AROs. As a result of a change in the estimated timing of cash flows for the interim retirement of natural gas pipeline components, Questar Gas recorded an increase of $75.1 million to AROs in the third quarter of 2016. The current portion of the ARO balance is $1.6 million and is included in other current liabilities in the Balance Sheets. The ARO liability is adjusted to present value each period through an accretion calculation using a credit-adjusted risk-free interest rate. Changes in Questar Gas' AROs from the Balance Sheets were as follows:

	Amount
(millions)
AROs at December 31, 2014	$	0.6
AROs at December 31, 2015	$	0.6
Accretion	2.9
Revisions in estimated cash flows	75.1
Liabilities settled	(0.8		)
AROs at December 31, 2016	$	77.8