Meaning

An indifference as to the choice between options; one thing is as good as another.

Origin

From Shakespeare's Troilus and Cressida, 1601:

PANDARUS:
Because she's kin to me, therefore she's not so fair
as Helen: an she were not kin to me, she would be as
fair on Friday as Helen is on Sunday. But what care
I? I care not an she were a black-a-moor; 'tis all one to me.

See other phrases and sayings from Shakespeare.