Story highlights Adelson's decision is a boon for Trump

Adelson will likely direct at least $5 million to the Ricketts political operation

Washington (CNN) Conservative megadonor Sheldon Adelson and his wife, Miriam, have committed roughly $45 million so far to Donald Trump's presidential campaign and downballot Republicans' attempt to control Congress, according to a person familiar with Adelson's thinking.

The billionaire on Tuesday will disclose having given $20 million to the Senate Leadership Fund, a super PAC linked to George W. Bush hand Karl Rove and Senate Majority Leader Mitch McConnell.

A check of a similar size is expected to go to the Congressional Leadership Fund, a similar super PAC focused on the House of Representatives.

And to back Trump, a donation of at least $5 million is likely headed to the political operation helmed by the Ricketts family, who are expected to finally spend their fortunes on Trump as well. Other cash may be routed to Ricketts-led nonprofit groups that are not required to disclose the funders.

The spending amounts to a historic investment in the Republican Party ticket's hopes for November, putting millions of dollars behind Trump's bid in a groundbreaking donation that could redefine the final two months of the 2016 campaign.

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