using || in casewhen

hi guys
I have two tables

employee table has
Id salary   bonus
1  100       22
2  300        33
5  600

customer table has
Id salary  bonus
1   100     33
2   500      44
5   800

select e.id, case when e.salary != c.salary || e.bonus != c.bonus then 'false' else 'true' end status

getting error
ORA-00905: missing keyword
00905. 00000 -  "missing keyword"

any idea?

thanks