Concatenate distinct strings and numbers

Question

I am trying to get a distinct concatenated list of employee_ids and sum their employee_allowance. However, I do not want to sum duplicate employee_id's employee_allowance.

My expected result

name	employee_ids	allowance	this column is for explanation (not part of output)
Bob	11Bob532, 11Bob923	26	13+13=26 because the id's are different, so we sum both
Sara	12Sara833	93
John	18John243, 18John823	64	21+43=64 because we got rid of the duplicate 18John243's allowance

Table creation/dummy data

CREATE TABLE emp (
   name varchar2(100) NOT NULL,
   employee_id varchar2(100) NOT NULL,
   employee_allowance number not null
);

INSERT INTO emp (name, employee_id, employee_allowance) VALUES ('Bob', '11Bob923', 13);
INSERT INTO emp (name, employee_id, employee_allowance) VALUES ('Bob', '11Bob532', 13);
INSERT INTO emp (name, employee_id, employee_allowance) VALUES ('Sara', '12Sara833', 93);
INSERT INTO emp (name, employee_id, employee_allowance) VALUES ('John', '18John243', 21);
INSERT INTO emp (name, employee_id, employee_allowance) VALUES ('John', '18John243', 21);
INSERT INTO emp (name, employee_id, employee_allowance) VALUES ('John', '18John823', 43);

My attempt

My output gives me the distinct, concatenated employee_ids but still sums up the duplicate employee_allowance row.

SELECT
  name,
  LISTAGG(DISTINCT employee_id, ', ') WITHIN GROUP (ORDER BY employee_id) "ids",
  SUM(employee_allowance)
FROM emp
GROUP BY
  name