The EU could quite easily become the biggest superpower on earth and presently, is much more powerful than Russia.
Russia of 70 years ago, is not the Russia of today. I'm convinced that when most people think of the military power of Russia, they think of a resurgent Soviet Union driving back besieged from all sides Nazis. The problem is this, warfare has changed, Russian politics have changed, economics have changed and Russian demographic superiority has changed.
Even just looking at the facts.
The population of the Soviet Union in 1940, 200 million. Russia today, 140 million
(and falling). The EU, 530 million, 4 times the population of Russia. That's crucial, because Russia's military power came from it's almost limitless manpower, either to feed the economy or serve in the military.
The GDP of the EU is about 8 times that of Russia. The EU has massive industrial capacity, Russia simply can't match it. Even if the comparison was just done on labour, the EUs huge advantage in that would give it the edge. But look at capital, the EU is way ahead of Russia. Then the research and technology available to the EU is just so far ahead of what Russia could muster.
Obviously the EU does not have a combined military, but if it did, it would be extremely formidable.