Answer:
accrued interest owed at the end of the year = $400 x interest rate x 6/12 months
the interest rate was not given, but we can assume that it was 5% just as an example:
total accrued interest expense = $400 x 5% x 6/12 = $10
the journal entry would be
December 31, 2021
Dr Interest expense 10 million
Cr Interest payable 10 million