WASHINGTON – A week after unveiling major veterans’ benefits legislation, Sen. Bernie Sanders still needs to work out some significant details — like how to pay for the bill.

“In terms of funding, we have not yet made a definitive decision,” said Sanders, chairman of the Veterans’ Affairs Committee.

Sanders, I-Vt., introduced the benefits package — the Comprehensive Veterans Health and Benefits and Military Retirement Pay Restoration Act of 2014 — last Thursday, calling his bill “the product of a year of bipartisan work” by his committee and “one of the most comprehensive pieces of veterans legislation introduced in decades.”

The sweeping legislation includes provisions for expanded access to dental care, in-state tuition costs for all veterans, regardless of residency, and better help for victims of sexual assault in the military. Sanders also wants to publicize Veterans Affairs Department claims records in order to shed more light on the department’s frustrating backlog problem.

The most notable provision in the bill would reverse cuts made to veterans’ pensions in the recently-signed spending bill. The budget bill drew the furor of veterans groups everywhere by reducing annual cost-of-living adjustments (COLA) by one percent for veterans under the age of 62.

Sanders, in a conference call Wednesday, said he “feels strongly” the COLA cuts should be completely repealed before taking effect next year.

But doing so would open up a budget deficit of about $6 billion. Sanders needs to cover that cost and fund the rest of the benefits bill, which he estimates would cost about $30 billion in total. He said he’s eyeing certain parts of the defense budget, like the $92 billion allotted to the Overseas Contingency Operation, which runs U.S. military operations in Afghanistan.

“Especially when you understand that OCO is designed for military purposes, I feel very comfortable that some of this money can be used for the people who defend us,” he said. “This is money for our defense, and I think it’s a very legitimate use of that money.”

Sanders said that Senate Majority Leader Harry Reid, D-Nev., told him he would get the benefits legislation moving “as quickly as possible.”

“It’s at the top of the list,” Sanders said.

How smoothly the bill moves through Congress, however, will depend largely on where the money comes from. Although politicians are reluctant to openly oppose increases to veterans’ benefits, it’s likely that opposition critical of the size and cost of the package will arise in both houses.

Even veterans groups that support Sanders’ efforts expressed doubts about funding the reforms.

“We look forward to working with you to see these provisions enacted into law, though we do have a concern regarding [the bill’s] budgetary implications,” wrote Charles Abell of Wounded Warrior Project in a letter to Sanders.

But Sanders remains optimistic that helping veterans is something both parties can get behind.

“What this bill does in a comprehensive way, is to say to the veterans of this country, the millions and millions of people who have given so much to us, is that we hear your concerns. And we are going to address your concerns.”