Unit of power in /sys/devices/system/cpu/cpu0/cpuidle/state0/power
IIRC, these values are taken from tables supplied by your BIOS, so it seems your motherboard vendor didn't bother filling in the correct information.
4294967295 is the 32 bit unsigned representationof the signed value -1. In other words this would be better output as -1 or "unspecified". State 0 is when the processor is running normally (not in an idle state) and the power usage in this state is highly variable.