for all (one) cares

One does not care (if something were to happen). The phrase always precedes or follows some hypothetical situation. You can starve to death for all I care. I am not giving you any more of my leftovers. Go to the police, for all I care! It's not like you have any evidence! Now that I know I'm not getting the promotion, they can pick any fool they want, for all I care.

for all I, you, etc. ˈcare

(spoken) used to say that a person is not worried about or interested in what happens to somebody/something: I could be dead for all he cares!

for all I, you, etc. care

for all (one) cares

for all I, you, etc. ˈcare