The split became effective as of 1 January 2016, 13 months after the company announced the move.
E.on will remain headquartered in Essen northwest Germany and be focused on renewables and energy networks.
The new company, Uniper, will operate from its headquarters in Dusseldorf and be active in conventional power generations – covering hydro, natural gas and coal – and energy trading.
At the time of the announcement in December 2014, explaining the thinking behind the split, E.on CEO Johannes Teyssen said: "E.on will tap the growth potential created by the transformation of the energy world. Alongside it we're going to create a solid, independent company that will safeguard security of supply for the transformation.
E.on's shareholders will be asked to approve the spin-off at the annual general meeting in June. If approved, E.on will divest its stake in Uniper and list its shares in the new company on the stock market.
E.on operates approximately 4GW of onshore wind capacity worldwide and owns over 1GW of offshore wind capacity.
It is also developing the 400MW Rampion offshore project, located off the UK's south coast.