The 2020 election has always loomed as the moment when Obama would step off the sidelines.
Bloomberg announced his departure from the race after a disappointing finish on Super Tuesday.
"Democrats take a huge risk if we just substitute one arrogant billionaire for another," says Senator Elizabeth Warren.
In victory speeches across the country, women acknowledge the groundbreaking year.
US president spent election night watching returns with family and friends at the White House.
Ilhan Omar and Rashida Tlaib are the first Muslim women to represent Americans in the US House of Representatives.
Republicans retain control of the Senate; Trump calls to congratulate Democratic Party House Leader Nancy Pelosi.
Spot gold rose 0.3 per cent to $1,235.10 per ounce as of 1154 GMT, while US gold futures were up 0.4s at $1,236.70.
Democrats claim that they are 100 per cent sure of reclaiming the House from Mr Trump’s Republicans.
Elections will decide whether Trump will keep his Republican majority in Congress or face a hostile Democratic majority.
Social media giant says it is further investigating suspicious accounts.
With political passions at a rare peak, early voting in some states is already running far ahead of normal levels.
The poll found Trump’s approval rating at its highest level for that poll yet, at 47 per cent.