Charles, who finished with 195 receiving yards on eight catches, became the first player in league history to grab four TD passes and add a rushing touchdown in a single game.
Alex Smith threw five scoring passes overall, completing 17-of-20 throws for 287 yards as the Chiefs (11-3) wrapped up an AFC post-season berth just one year after going 2-14.
On defense, Kansas City forced seven turnovers, including four interceptions of Oakland's Matt McGloin. Eric Berry had two of the pickoffs, including one returned for a touchdown.
McGloin made good on 18-of-36 passes for 309 yards and two touchdowns for the Raiders (4-10), who dropped a fourth straight.
Rashad Jennings led Oakland's ground game with 91 yards and two scores on 23 carries.
Pistorius testifies he didn't consciously pull trigger when he shot girlfriend
Biologists detail four new deep-sea 'killer sponges'