Khedira opened the scoring mid-way through the first-half. Ronaldo doubled the advantage after 70 minutes and Can added the gloss in stoppage time.
Massimo Allegri's men boast 63 points after 23 games and are still unbeaten in the top flight this season.
Juventus got the chance to increase their lead after Napoli drew 0-0 at Fiorentina on Satuday.
"We dropped two points that we would've deserved for attacking from start to finish," said Napoli boss Carlo Ancelotti after the stalemate.
"In some ways, it was an impeccable performance. But we weren't clinical enough in front of goal and were forced to make do with a point."
Juventus can go 14 points on 15 February when they host second from bottom Frosinone.