My client is a collectively-bargained mutliemployer plan, one employer withdrew from the plan. The actuary determined the withdrawal liability to be, say, $2 millions and the employer agreed to pay in quarterly installments with interests over 5 years. The question is how should the plan record this? Should the plan record the full $2 millions as receivable and contribution, and record installment payments as reduction to the receivable using an amortization schedule? Or should it record the installment payments as contributions and interests when received? Also, I need to have some backups to any answers provided. Thanks in advance.

You should record the entire principal amount as a receivable since it sounds like it has been determined to be due. You also have to consider collectability issues and possibly an allowance for doubtful accounts if warranted.

See AEBP at 2.38.