MCKESSON CORP | 2013 | FY | 3

 
Years Ended March 31,
(In millions)
2013
 
2012
Benefit obligation at beginning of period
$
144

 
$
152

Service cost
2

 
2

Interest cost
6

 
7

Actuarial gain
(9
)
 
(4
)
Benefit payments
(12
)
 
(13
)
Benefit obligation at end of period
$
131

 
$
144

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