The Secret Service plans to spend $220 million on White House East Wing security measures related to President Donald Trump’s ballroom project as part of a broader $1 billion in security spending Republicans are proposing, according to specific details shared with GOP senators Tuesday.

Secret Service Director Sean Curran met Tuesday with Senate Republicans to discuss the funding, which is part of the GOP’s budget reconciliation legislation that seeks billions of dollars for Immigration and Customs Enforcement and the Border Patrol after a stalemate with Democrats.

Senate Republicans aim to vote next week on the legislation. But some Republican senators have expressed concerns about the security funding portions of the legislation, and several said after Curran’s briefing at the party lunch they need more specifics before agreeing to support the spending.

Ahead of that meeting, Majority Leader John Thune estimated that about 20% will go to East Wing security.

“The balance of it is just going to other Secret Service priorities and technology and things they need to do to protect the president,” Thune (R-S.D.) told reporters.

The majority of the $1 billion would support the Secret Service’s core missions, while hardening the East wing will protect the First Family and visitors, according to a spokesperson from the Department of Homeland Security.

The Secret Service plans to spend $220 million to harden the East Wing extension, including installing bulletproof glass, drone detection, biological threat filtration and detection, and other national security functions, according to a breakdown of the agency’s request obtained by Bloomberg Government.

The remainder of the funding breakdown includes $180 million for improvements to security screening for staff and visitors to the White House complex, $175 million for both training facilities for Secret Service agents and boosting protectee security, $100 million for security for high-profile national events, and $150 million for a range of operations support to counter biological threats and airspace incursions, according to the document.

“It was a good back and forth,” Thune said after the lunch. “Obviously, we had a lot of questions that were asked by our colleagues just to get the details and precision as much as possible about how dollars are going to be used.”

Some Republicans left the lunch unsatisfied with the agency’s briefing, saying they would need more information before could support the security spending included in the package.

“They need to go back and get us more details about exactly, you know, how they arrived at the figure,” said Sen. Todd Young (R-Ind.).

Sen. John Kennedy (R-La.) said he’s writing an amendment that would decrease overall spending on the Department of Homeland Security by $1 billion to offset the amount of money for Secret Service.

Senators can force an unlimited number of votes on changes to the bill when it comes up on the floor next week. Kennedy said he asked Curran about the amendment, but the director “deferred to his higher ups.”

“It’d be a wash, it wouldn’t add to the deficit,” Kennedy told reporters. “I don’t know what kind of appetite there will be for that.”

The price tag alone is prompting lawmakers to ask questions about how that much money would be spent, said Rep. Dusty Johnson (R-S.D.).

“I don’t think we know exactly how this shakes out yet,” he told reporters.

Enough uncertainty about the proposal could prompt lawmakers to ultimately to shift the language in another legislative vehicle, said House Budget Committee Chairman Jodey Arrington (R-Texas).

“There’s lots of hypothetical outcomes,” he told reporters.

Democrats are broadly opposed to the GOP’s proposal, which is funding immigration enforcement through the budget reconciliation process to sidestep the 60-vote threshold required to pass most legislation in the chamber. The minority party is planning to keep the focus on the ballroom money and affordability as they work through procedural challenges and the amendment process.

“At the very moment Americans are pleading for relief, Republicans are saying, ‘Pay for Trump’s palace first,” Minority Leader Chuck Schumer (D-N.Y.) said.