Mel Gibson's Ex-Wife Gets Big Piece of Pie in Divorce

Mel Gibson's ex-wife Robyn snagged a big chunk of Mel's retirement package ... TMZ has learned.
According to documents filed in the couple's divorce case and obtained by TMZ, Robyn got the following:

-- Half of the Screen Actors Guild pension benefits Mel accumulated during the 31 years of their marriage.

-- A big chunk of Mel's Directors Guild of America pension benefits

-- Half of the 401(k) benefits their production company -- Icon -- accumulated during their marriage.

As TMZ previously reported ... the couple also divided earnings and property ... roughly estimated at $800 million and we're told Robyn got roughly half.

Mel Gibson and Robyn Gibson are officially single -- a judge signed the divorce decree moments ago.

The only big change -- Robyn is going back to her maiden name ... so from now on it's Robyn Moore.

As we reported, the couple's been negotiating a financial settlement for over a year ... and we're told, it's finally a done deal. There is no prenup.

The couple's reported net worth is in the $900 million range -- but sources tell us, it's actually less.

Mel was represented by Larry Ginsberg.

Robyn -- who was repped by disso-queen Laura Wasser -- filed for divorce in 2009 following a three-year separation -- shortly after learning Mel's then GF Oksana Grigorieva was pregnant.