The Democrats have managed to hold onto the Senate, after reaching the magic number of 51 seats.
Obama’s party lead the Republicans with a 51-44 lead, with two individual seats and three still to come in.
The House of Representatives remains largely in favour of the Republicans though, with a total of 208-150 in favour of the Republicans being totalled at this moment.
See here, for a quick look at the background of the Senate and the House of Representatives.