diff --git a/addons/account/account.py b/addons/account/account.py
index f0c16d8586c..a441a262003 100644
--- a/addons/account/account.py
+++ b/addons/account/account.py
@@ -1363,7 +1363,7 @@ class account_move(osv.osv):
         balance = 0.0
         for line in line_ids:
             if line[2]:
-                balance += (line[2]['debit'] or 0.00)- (line[2]['credit'] or 0.00)
+                balance += (line[2].get('debit',0.00)- (line[2].get('credit',0.00)))
         return {'value': {'balance': balance}}
 
     def write(self, cr, uid, ids, vals, context=None):