Power is measured at a point in time, so it is best to plot the values you are interested in an analyze the plot.
Alt-Click (left click) on a component to plot its power. The, in the plot plane, you can Ctl-Click the name of the trace ("V(N016)*I(R1)" or whatever) to get the Average, Integral, and other things. You can also right-click to edit the expression, so that you can, for example, combine power dissipation of two components together in a single plot.
You can also the .MEASURE to do powerful things. Look up the help. A simple example is:
.measure TotalFetPower AVG V(N016)*I(R1)+V(N017)*I(R2)
.measure TotalPeakFetPower MAX V(N016)*I(R1)+V(N017)*I(R2)