XML 67 R20.htm IDEA: XBRL DOCUMENT v2.4.0.6
Asset Retirement Obligations (Tables)
 3 Months Ended
Mar. 31, 2013
Asset Retirement Obligation [Abstract]  
Changes in AROs
Changes in Questar's AROs from the Condensed Consolidated Balance Sheets were as follows:
 
3 Months Ended
 
March 31,
 
2013
 
2012
 
(in millions)
AROs at beginning of year
$
67.2

 
$
63.8

Accretion
0.8

 
0.7

Liabilities incurred
0.4

 
0.7

Revisions in estimated cash flows
(6.8
)
 
(1.1
)
Liabilities settled
(0.4
)
 
—

AROs at March 31,
$
61.2

 
$
64.1