Negative Debits Or Credits In Table

I have a table with debits and credits columns

Credit Debit
-7600
0080
90-30

I am transferring the debits and the credits in to one column in another table

Type Amount
C-76
D80
C90
D-30

And I am facing two problems one is the negative numbers don't transfer and also when I have debit and credit on the same line they are not transferring.

Select Case When isNull(A.[Debit], 0) > 0 And IsNull(A.[Credit], 0) = 0 Then 'D' Else 'C' End,
Case When isNull(A.[Debit], 0) > 0 And IsNull(A.[Credit], 0) = 0 Then Round(A.[Debit],2) Else Round(A.[Credit],2) End
FROM Tble A