How can I update a value for a key in a jsonb object using a reference to the value itself?

I'm trying to update a key's value in a JSONB data type with a reference to itself. Basically I have to replace any negative values with it's positive.

I've tried this, and I can't seem to get it to work:

UPDATE transactions 
   SET raw_transaction = JSONB_SET( raw_transaction, '{transaction-amount}', 
                            ABS ( ( raw_transaction ->> 'transaction-amount' )::DECIMAL ), 
                            FALSE ) 
 WHERE ( raw_transaction ->> 'transaction-amount' )::DECIMAL < 0 

Sample data

{
  "id":"wkjhen87398", 
  "transaction-amount":-1.23
}

Any help would be much appreciated.

Solved it with a few extra casts:

UPDATE transactions 
   SET raw_transaction = JSONB_SET( raw_transaction, '{transaction-amount}', 
                            ((ABS ( ( raw_transaction ->> 'transaction-amount' )::DECIMAL))::TEXT)::JSONB, 
                              FALSE ) 
 WHERE ( raw_transaction ->> 'transaction-amount' )::DECIMAL < 0