In the System Information screen, Jupiter is listed as having the same magnetic field strength as Earth. According to Wikipedia, this should be around 20 times that of Earth. (Unless I misinterpreted "magnetic field" and it's measuring something different instead. )
(Also, Saturn should be somewhat less than Earth, but the two are listed as having the same magnetic field. They're close enough that it's tricky, since magnetic field strength varies over the surface of Earth, but Saturn's average is less than the typical minimum for Earth, so it should be something from 0. 32 to 0. 84. )