I know this is an old thread but I went searching today to see if there was a better method of finding which statement periods transactions are cleared to. So far this is the best solution I have found.

Change the cleared transaction amount by .01 . Go to Reports>Banking>Previous Reconciliation Discrepancy Report. Select the reconciled account. The modified transaction will appear on the discrepancy report, below the statement date that it was reconciled with. Remember to change the transaction back to the cleared amount or the reconciliation will be out of balance.