The roll forward of the pension plan assets for level 3 reconciles between the opening plan assets less any sales of the assets plus any purchases. Payments of benefits are not included in this roll forward as the sale of the plan assets is used to pay the benefits. However, there are no elements defined in the taxonomy for the sale and purchase of plan assets. Instead companies have used the tag DefinedBenefitPlanDivestituresPlanAssets to represent the sale of plan assets. The element is defined as the “decrease in the plan assets attributed to the sale, liquidation, spin-off or other divestiture of a corporate division or subsidiary.” Clearly this element should not be used for sales of securities that were used to pay benefits and to buy another type of security.
In addition no tag exists for purchases of plan assets. In the graphic below we can see that the company has reported Purchases of 7 and Sales of (25) for the change in plan assets at fair value. Both of these disclosure items are not included in the pension section of the taxonomy.
Create extension elements to represent the purchase and sales of plan assets. The following element names should be used for the extension:
DefinedBenefitPlanPurchasesOfPlanAssets -> Duration Period Type -> Debit Balance Type
DefinedBenefitPlanSalesOfPlanAssets -> Duration Period Type -> Credit Balance Type
DefinedBenefitPlanNetPurchasesSalesOfPlanAssets -> Duration Period Type -> Debit Balance Type
These extension elements should not be used in the rollforward of overall plan assets defined in section 730000 of the pension disclosure under the abstract element DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward, which should be used when applicable for the rollforward of level 3 assets. However, when a purchase or a sale moves assets between hierarchies then the above extension elements should be used. It is expected that these extension elements would only be used in the roll-forward where the plan assets are disaggregated by the fair value hierarchy (as shown in the figure above) or asset class.