Even $20 million can't lure Katy Perry onto American Idol. Apparently trying to upgrade its judges from musical has-beens to superstars, Idol offered her $18 million and tossed in another $2 million for a single season's work—to no avail, TMZ reports. Sources say she didn't object to the money, but has a busy schedule and doesn't like backwards career moves. Quips TMZ: "Mariah must be one pissed, $18 million judge." (More Katy Perry stories.)