It is beyond doubt that Russia invented fake news stories to help Donald Trump win the election. Social media sites have all admitted they were used in this way -- and are currently being grilled by Congress about it. In addition, Congress applied new sanctions against Russia for this behavior.
But if there's anything Trump voters are good at -- it's denying reality (no matter how much evidence is revealed). About 78% of Trump voters don't believe the Russians created and spread fake stories to help Trump (38% say it definitely didn't happen and 40% say it probably didn't happen). Only a tiny 22% say it probably (20%) or definitely (2%) happened.
This chart shows results from a new Economist / YouGov Poll -- done between October 29th and 31st of a random national sample of 1,500 adults (including 497 Trump voters), with a 3 point margin of error.