The capital, infrastructural and natural, and the factors of products MINUS financial capital and the workers. Simply put, the financial capital is NOT a mean of production because no matter how much money someone has, only he who owns a factory can process natural goods and make e.g. food to eat and survive.
Factories, transport ships and airplanes... Also the media.
Utopian ideals of a society where true wealth -the means of production- belong to the public, and the products' quality advances not by the need in market, but by sheer willpower to make a better world. Thus utopian.
Russia during Stalin's reign is a perfect example of actually existing communism. It had nothing to do with theoretical communism which is based on a notional society.