The steam turbine has an exhaust-steam casing that can be adapted to various combinations of an inlet casing, connected upstream of the exhaust-steam casing, and a condenser especially simply while maintaining favorable flow properties of the exhaust steam. To this end, the outer jacket of the exhaust-steam casing has a first jacket part in the shape of a cylindrical jacket, which is connected via a stiffening ring to a second jacket part in the shape of a conical jacket. A guide element in the shape of a conical jacket is arranged on the stiffening ring in order to direct the exhaust-steam flow inside the outer jacket.