Tomlinson finished the day with 116 yards on 15 carries and Philip Rivers was 14-of 21 passing for 142 yards and a touchdown for the Chargers (9-5), who have snagged their second straight division title.
Darren Sproles also had 25 carries for 122 yards and two scores for San Diego, which has won six straight against Detroit.
Jon Kitna completed 26 out of 46 passes for 302 yards and two touchdowns, but was picked off five times for the Lions (6-8), who are now virtually eliminated from playoff contention.
Calvin Johnson also had five catches for 102 yards for Detroit.
Notable deaths of 2014 [PHOTOS]