VALERO ENERGY CORP/TX | 2013 | FY | 3


Changes in our asset retirement obligations were as follows (in millions).

 
Year Ended December 31,
 
2013
 
2012
 
2011
Balance as of beginning of year
$
108

 
$
87

 
$
101

Additions to accrual
2

 
14

 
3

Revisions in estimated cash flows

 
13

 
1

Accretion expense
2

 
5

 
4

Settlements
(1
)
 
(11
)
 
(22
)
Separation of retail business
(80
)
 

 

Balance as of end of year
$
31

 
$
108

 
$
87


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