President Donald Trump has announced a one-time $90 payment to help more than 20 million seniors cover Medicare premiums ahead of the Nov. 3 midterm elections.

The White House said eligible Medicare Part B enrollees can expect the payment in October by direct deposit or check. It will come from the Medicare Improvement Fund, which Congress established in 2008 to support program operations and payments to health care providers.

Eligibility is limited to seniors living in the United States who do not already receive Medicaid help with premiums or pay income-adjusted premiums, according to the Centers for Medicare and Medicaid Services. People enrolled in Medicare Advantage are excluded.

Trump announced the plan on social media late Friday. Last month, he said about 1 million people would receive $500 rebates for Affordable Care Act premiums.