Code:
Connected to:
Oracle9i Enterprise Edition Release 9.0.1.1.1 - Producti
With the Partitioning option
JServer Release 9.0.1.1.1 - Production

SQL> SELECT * FROM your_table;

        ID WHO                       MONEY
---------- -------------------- ----------
         1 Henry                        10
         2 John                          5
         3 John                         10
         4 Mario                        20

SQL> SELECT id, who, SUM(money) FROM your_table
  2  GROUP BY rollup(who, id);

        ID WHO                  SUM(MONEY)
---------- -------------------- ----------
         1 Henry                        10
           Henry                        10
         2 John                          5
         3 John                         10
           John                         15
         4 Mario                        20
           Mario                        20
                                        45

8 rows selected.
Those rows in bold are subtotals (the last one is grandtotal) that were added by ROLLUP.