Billionaires Mike Bloomberg and Tom Steyer became powerful kingmakers for Democrats running to unseat Republicans in this year's midterm elections as they each contemplate a run for president in 2020.

Bloomberg became a game-changing figure for Democrats as his candidates stormed the U.S House of Representatives to help retake the majority.

Based on voting projections, Bloomberg is expected to see 21 of the 24 House candidates he supported through his super PAC Independence USA win their races.

Those candidates include former Obama official Haley Stevens who is projected to be the first Democrat to hold Michigan's 11th District since the late 1960s and former NFL linebacker Colin Allred in Texas' 32nd District who overtook longtime GOP Rep. Pete Sessions.

The PAC spent $2 million in support of Stevens and $1.4 million against Sessions, according to the nonpartisan Center for Responsive Politics. Most of the PAC's funds in 2018 went toward TV and digital ads.

Democrats clinched the 218 House seats they needed to become the majority. There are at least 15 additional toss-up seats that have yet to be called.

In a press release on Wednesday, Bloomberg's chief spokesman, Stu Loeser, said the former New York City mayor spent more than $110 million to elect Democrats this year.

Bloomberg celebrated the victory by taking aim at President Donald Trump's administration.

"By winning the House, Democrats can now serve as a bulwark against a White House that has shown no respect for the rule of law - and no interest in bringing the country together." Bloomberg said in a statement. "The Democrats' gains demonstrate that the American people want Congress to stand up to a reckless, divisive president - and to work across the aisle to tackle tough issues. Millions of Americans poured their hearts into the campaign to retake the House - and I was proud to be a part of the effort. We can do better in America today, and we must start now," he added.

There was one investment that didn't pan out for Bloomberg and that was his $20 million contribution to the Senate Majority PAC, a super PAC intended to help Democrats make inroads in the U.S. Senate.

Democrats so far have lost at least three Senate seats to Republicans: Indiana Sen. Joe Donnelly, Missouri lawmaker Claire McCaskill and one-term Sen. Heidi Heitkamp of North Dakota. Democratic Sen. Bill Nelson of Florida called for a recount after NBC News projected that his race with the state's former governor, Rick Scott, was too close to call. Montana Democratic Sen. Jon Tester was named the apparent winner by NBC News on Wednesday.

Democrats picked up one seat in Nevada as U.S. Rep. Jacky Rosen is the projected winner over Republican incumbent Sen. Dean Heller. They may also add a seat in Arizona but that race is still too close to call.