XML 62 R32.htm IDEA: XBRL DOCUMENT v2.4.0.8
Asset Retirement Obligations (Tables)
 12 Months Ended
Dec. 31, 2013
Asset Retirement Obligation [Abstract]  
Asset retirement obligations roll forward
The following is a reconciliation of the changes in the Company's ARO for the periods specified below:
 
 
Asset Retirement Obligations
 
2013
 
2012
 
(in millions)
ARO liability at January 1,
$
193.1

 
$
163.9

Accretion
8.9

 
10.5

Liabilities incurred
11.0

 
8.5

Revisions
(4.4
)
 
11.1

Liabilities related to assets sold
(11.4
)
 
—

Liabilities settled
(3.6
)
 
(0.9
)
ARO liability at December 31,
$
193.6

 
$
193.1