diff --git a/addons/hr_payroll/report/report_payslip_details.py b/addons/hr_payroll/report/report_payslip_details.py
index 45d35373455..f521cdb320d 100644
--- a/addons/hr_payroll/report/report_payslip_details.py
+++ b/addons/hr_payroll/report/report_payslip_details.py
@@ -41,7 +41,7 @@ class payslip_details_report(report_sxw.rml_parse):
             if not rule_categories:
                 return []
             if rule_categories[0].parent_id:
-                rule_categories.insert(0, rule_categories[0].parent_id)
+                rule_categories = rule_categories[0].parent_id | rule_categories
                 get_recursive_parent(rule_categories)
             return rule_categories