Elon Musk, the world's only trillionaire, has quietly become the biggest known donor in this year's midterm elections, doling out more than $276 million since July to try to save Republican majorities in Congress.

The numbers, first reported by the New York Times ahead of this week's federal filing deadline, were confirmed by Andrew Romeo, a spokesperson for Musk's super PAC.

The money includes $158 million given to the Senate Leadership Fund, the main super PAC supporting Republican Senate candidates, one of the largest known political donations in American history, according to the Times.