Yes, typically Volker is correct, if you add another 0.2 dB or so for circuit losses.
But there are other scenarios.
There is a "resistive" power splitter. It is composed of 3 resistors in a star or delta--no transmission lines involved. That has maybe 6.3 dB of loss.
Also, for the wilkenson splitter, you can use it like a power combiner with 0 dB loss. Say you have a signal that you input to the splitter. The 2 outputs are 3 dB down. Then you pass both of the signal thru some RF circuit (say a shunt varactor diode with no loss but some phase shift). The 2 signals then arrive (both with the same phase shift) to a 2nd wilkenson. They recombine with NO loss vectorially at the wilkenson output. This is because the 2 signals in either wilkenson are IN PHASE, so no current flows thru the resistors.