For the second consecutive quarter, Brad Parscale, Mr. Trump’s campaign manager, declared the incumbent to be building a financial “juggernaut” for the general election. His $102.7 million war chest will be supplemented by tens of millions of dollars more in the coffers of the Republican National Committee, which Mr. Trump functionally controls.

Together, Mr. Trump’s re-election campaign and the Republican National Committee raised roughly $125 million in the third quarter, and a Trump campaign official said on Thursday that their combined total for the fourth quarter would be even larger.

But Democrats were heartened that, collectively, their campaigns far surpassed the total of Mr. Trump’s re-election campaign; the full field of 14 candidates will more than double the president’s take, signaling the intense desire in the party to win back the White House.

“What you’re seeing is a Democratic base so aware and so paying attention so early on,” said Karine Jean-Pierre, a Democratic strategist and a spokeswoman for MoveOn.org, a progressive activist group. “It’s just been part of the reaction to Trump. The last three years we’ve seen a very engaged Democratic base.”

The full picture of the financial race will not become clear until Jan. 31, when all the candidates must file their fund-raising reports with the Federal Election Commission. How much money the Democratic candidates actually have in the bank to spend in the closing stretch is an even more significant metric of their viability so close to votes being cast; notably, no Democrats have voluntarily disclosed that information.

Still, Mr. Sanders enters 2020 with a clear financial advantage over his primary rivals: His treasury allows him to buy additional television ads in the early states — he purchased new airtime in New Hampshire on Thursday — and to invest in staff in Super Tuesday states like California, where he had already dispatched 80 staff members as of December.