Enable, the 10-11 favorite, led for most of Europe's richest horse race to claim her fifth consecutive victory after wins in the Epsom Oaks, the Irish Oaks, the King George VI & Queen Elizabeth Stakes and the Yorkshire Oaks.
The John Gosden-trained filly won by 2 1/2 lengths over Cloth Of Stars, ridden by jockey Mickael Barzalona and trained by Andre Fabre.
The Michael Stoute-trained Ulysses, ridden by Jim Crowley, was another length and a quarter back in third.
"I said to John last week she is the best she has ever been. To keep this filly at 100 percent all year is fantastic," Dettori said. "I had position 'A', I knew I had no weight and she stays, so I kicked and she gave me four lengths and the race was over.
"She's amazing and is an absolute freak. I love her. John is a genius."
It was Dettori and Gosden's second Arc win in three years, after the popular Italian won on Golden Horn.
Dettori's victory comes 22 years after his first triumph in the 1 ½-mile race.
The 3-year-old Enable made a fast start from stall two and Dettori always had her well positioned behind Aidan O'Brien's pair of Idaho and Order Of St George, before pulling away inside the final two furlongs
"She showed an impressive turn of foot and acceleration to kill the field. She has amazing ability," Gosden said. "Frankie got her in a great position. He's pretty good for an old jock!"
The race will return to its usual home at Longchamp in 2018 after a two-year absence due to renovations, and Gosden hopes Enable will be there.
"She has only raced for 10 months of her life. She had one little run last November, but really she's only had one season of racing," Gosden said. "There would be every reason to keep her in training next year as a 4-year-old, particularly with the new Longchamp opening.
"That would be exciting - to try to win the Arc on two different tracks."
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