The reports say McCartney would also provide $4 million for maintenance of the couple's four-year-old daughter, Beatrice, according to CBS News correspondent Elizaberh Plamer.
McCartney arrived at court Tuesday looking remarkably upbeat for a man in the middle of a costly and acrimonious divorce, Palmer observed.
Although the story is on the front of almost every paper in Britain Tuesday, the actual court proceedings in the ultra-high-profile case are firmly closed to the public, Palmer notes, and expected to go on all week -- with air-tight security so far keeping the celebrity-hungry paparazzi firmly out in the street.
Mills is reported to be seeking compensation because, she contends, her life has been ruined by her marriage to McCartney.
Before she met him, as an amputee, she was popular as a charity speaker, Mills is said to be arguing, but since the breakup, Mill says, she's become a hate figure.
An emotional Mills recently told the British Broadcasting Corporation, "I've had 18 months of this abuse, and it's come from everywhere -- behind-the-scenes, in front of the scenes -- everywhere. And now, -- death threats."
Mills had a falling out with her lawyers months ago and has, Palmer says, made the decision -- some say an unwise one -- to represent herself in divorce court.
"In terms of the niceties of the legal arguments she wants to put across," says family law solicitor Ayesha Yardag, "she's going to be a little bit at sea, as any lay person would, and this isn't going to be an opportunity in which the sort of soapbox grandstanding, very impassioned pleas are really going to cut a lot of ice."