Asset Retirement Obligations
 12 Months Ended
Dec. 31, 2015
Asset Retirement Obligation [Abstract]  
Asset Retirement Obligations
Asset Retirement Obligations
Changes in the Partnership’s liability for asset retirement obligations for the years 2015 and 2014 are presented in the table below:
(in millions)
2015
 
2014
 
 
 
Predecessor
Balance as of January 1,
$
23.2

 
$
26.3

Noncontributed net parent investment adjustments(1)
(0.4
)
 
—

Accretion expense
1.2

 
1.5

Additions
4.1

 
2.2

Settlements
—

 
(6.6
)
Change in estimated cash flows
(2.8
)
 
(0.2
)
Balance as of December 31,
$
25.3

 
$
23.2


(1) Reflects the removal of amounts related to Crossroads Pipeline Company, which was included in the Predecessor, but was not contributed to the Partnership.
The asset retirement obligations above relate to the modernization program of pipelines and transmission facilities, the retiring of offshore facilities, polychlorinated biphenyl ("PCB") remediation and asbestos removal at several compressor and measuring stations. The Partnership recognizes that certain assets, which include gas pipelines and natural gas storage wells, will operate for an indeterminate future period when properly maintained. A liability for these asset retirement obligations will be recorded only if and when a future retirement obligation with a determinable life is identified.