The Democratic Socialists of America is the largest such group in the United States (formed in 1982 by a merger of the New American Movement—a group I was in—and the Democratic Socialist Organizing Committee, a remnant of the old Socialist Party of America. Today the stated view of DSA (which has formally endorsed Sanders) is this:
Democratic socialists do not want to create an all-powerful government bureaucracy. But we do not want big corporate bureaucracies to control our society either. Rather, we believe that social and economic decisions should be made by those whom they most affect.
Today, corporate executives who answer only to themselves and a few wealthy stockholders make basic economic decisions affecting millions of people. Resources are used to make money for capitalists rather than to meet human needs. We believe that the workers and consumers who are affected by economic institutions should own and control them.
Social ownership could take many forms, such as worker-owned cooperatives or publicly owned enterprises managed by workers and consumer representatives. Democratic socialists favor as much decentralization as possible. While the large concentrations of capital in industries such as energy and steel may necessitate some form of state ownership, many consumer-goods industries might be best run as cooperatives.
Democratic socialists have long rejected the belief that the whole economy should be centrally planned. While we believe that democratic planning can shape major social investments like mass transit, housing, and energy, market mechanisms are needed to determine the demand for many consumer goods.
Obviously, not every democratic socialist is a member of DSA, including Sanders himself. And other democratic socialists take a different view on some matters. But the approach laid out above is clearly not the authoritarian socialism that some would like to make of it.
[Full disclosure, I was a member of New American Movement from 1971 until it merged with DSOC in 1982 to become DSA, a group I have been associated with since then.]