XML 54 R31.htm IDEA: XBRL DOCUMENT v3.10.0.1
Summary of Significant Accounting Policies (Tables)
 12 Months Ended
Dec. 31, 2018
Accounting Policies [Abstract]  
Schedule of Change in Asset Retirement Obligation
The following table presents the change in the liability for asset retirement obligations, of which $107 million, $99 million and $33 million were reflected in “Other long-term liabilities and deferred credits” with the remaining portion reflected in “Other current liabilities” on our Consolidated Balance Sheets as of December 31, 2018, 2017 and 2016, respectively (in millions):

 
December 31,
 
2018
 
2017
 
2016
Beginning balance
$
103

 
$
44

 
$
35

Liabilities incurred
3

 
33

 
20

Liabilities settled
(3
)
 
(4
)
 
(3
)
Accretion expense
4

 
3

 
1

Revisions in estimated cash flows
2

 
27

 
(9
)
Ending balance
$
109

 
$
103

 
$
44