WASHINGTON (AP) — Deep-pocketed donors are turning over multimillion-dollar checks to influence November’s elections, and the sums raised by the national parties and their super PAC allies are already approaching the $1 billion mark, according to financial reports still being filed Tuesday evening.

An imprecise snapshot of political giving is coming into focus as outside organizations detail their fundraising and spending through March 31. The enormous sums of money do not capture what federal candidates themselves are raising and spending. In other cases, some of the most active outside groups operate under rules that allow them to keep many details of their finances secret.

Democrats, at least for the moment, seem to have a roughly 3-to-1 advantage over Republicans in cash raised and banked through independent groups, according to the early filings. That balance of power could quickly change as new reports are filed with the Federal Election Commission.

And those early figures lack details from some of the more influential Republican groups that have great sway over elections but whose names never appear on ballots.

For instance, National Rifle Association Political Victory Fund has until Sunday to file its reports. Through the end of February, the Republican-leaning group had raised almost $14 million.

And Americans for Prosperity, one of the most aggressive in running ads against Democrats as part of the billionaire Koch brothers’ network of conservative groups, does not have to disclose its donors because, under tax rules, it is technically not political. Democrats have been relentless in criticizing Charles and David Koch’s role in helping Republican candidates.

Groups that disclose whose money is coming in and how much is going out on a quarterly basis faced a midnight Tuesday deadline. Groups that release that information on a monthly basis have until Sunday to post their reports.

Already, it looks as though total outside fundraising soon will be hitting the $1 billion mark, a sum comparable to what President Barack Obama, the Democratic National Committee and his top super PAC spent to win a second term in 2012. His Republican rival, Mitt Romney, and his allies spent about the same to come up short.

But those sums were over two years of campaigning. The 2014 campaign still has eight months to go.

Among the groups that had filed their reports, some donations were catching attention.

Fred Eychaner, the founder of Chicago-based Newsweb Corp., wrote a $4 million check to the Senate Majority PAC, a Democratic group with ties to Senate Majority Leader Harry Reid. The group raised $11 million during the first three months of the year, including $2 million from James Simons, founder and chairman of investment firm Renaissance Technologies.

Retiring Sen. Jay Rockefeller wrote the group a $250,000 check to help fellow Democrats keep their advantage. His retirement opens the door for Republicans to win that seat in West Virginia.

Republicans need to net six seats to claim the majority in the Senate.

Committees affiliated with autoworker, teacher, municipal worker, engineer and pipefitter unions all gave six-figure donations to the group. All told, organized labor directed at least $2.5 million through the super PAC to help Democrats hold the Senate.

Reid’s political action committee also wrote the group a $100,000 check to keep Reid atop the Senate. A group affiliated with Sen. Tim Kaine of Virginia known as Common Ground PAC donated $50,000.

The super PAC is sitting on almost $20 million to help defend Democrats’ majority.

EMILY’s List, which aims to elect female pro-abortion rights candidates, raised more than $2.5 million in March, bringing its total sum to almost $25 million this election cycle.

For other groups trying to help Democrats, the reports showed who was not giving.

San Francisco investor Tom Steyer founded NextGen Climate Action in 2013 and sent to it $9.3 million from his billion-dollar fortune. The group spent almost $8.3 million in 2013 and Steyer pledged $100 million to influence 2014’s elections. Yet the group raised roughly $30,000 from two donors so far this year; neither was Steyer. NextGen spent close to $500,000 and has about $870,000 in the bank.

After spending $75 million to help Obama’s re-election, Priorities USA Action stuck with its plans not to raise money in 2014. Its report showed just three individual donors, totaling about $4,000. The organization, which is preparing to support a potential 2016 presidential bid from Hillary Rodham Clinton, urged donors to give to other groups.

To help Republicans pick up seats in the Senate, the Karl Rove-backed American Crossroads super PAC stepped up its fundraising. The group raised more cash in March than it did during the previous 14 months combined.

The GOP establishment’s favorite super PAC raised almost $5.2 million in March and had more than $6.3 million in the bank as of March 31. That cash already has been used to criticize incumbent Democratic senators in Alaska and North Carolina and is expected to support former Massachusetts Sen. Scott Brown in his bid to unseat Democrat Jeanne Shaheen in New Hampshire.

“There’s been a noticeable rise in enthusiasm among our donors,” American Crossroads chief Steven Law said, crediting candidates challenging Democratic incumbents.

American Crossroads accepts unlimited donations and spent more than $116 million on the last election cycle. It is now positioning itself to be a major player during these midterm elections as it accepts unlimited donations.

Both parties’ committees to elect House members were expected to file their reports before Sunday’s deadline. The Democratic National Committee, which went into March with more than $15 million in debt, also had not announced how much it raised and spent in March.

Among other party committees, the Republican National Committee said it raised $10.2 million in March and had $12 million in the bank. The National Republican Senatorial Committee reported it raised almost $6.4 million in March and had almost $15.9 million saved.

The Democratic Senatorial Campaign Committee said it raised $8.1 million in March and was sitting on $22.2 million.

House and Senate incumbents and challengers were also filing reports. A snapshot of their finances was slower to come together, but the dollars under candidates’ direct control certainly would have their own influence on November’s elections.

For instance, Senate incumbents and challengers came into this election year with almost $200 million raised and about $158 million saved for what is expected to be a brutal fight for control of that chamber.

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