Sen. Bernie Sanders (I-Vermont) said he does not think he has to release details on how his Medicare for All healthcare would be funded, although he has previously said taxes on both the middle and upper class would increase.

In an interview released Tuesday with CNBC’s John Harwood, Sanders seemed uncertain of exactly how much taxes would increase per person.

“You’re asking me to come up with an exact detailed plan of how every American — how much you’re going to pay more in taxes, how much I’m going to pay. I don’t think I have to do that right now,” Sanders told Harwood.

Democratic candidate Sen. Elizabeth Warren (D-Massachusetts) has a similar government-funded healthcare proposal, but said she will release her plan to pay for it. She has previously been criticized for dodging questions about how much it will cost the middle class.

In early November, she rolled out her first healthcare proposal that would cost $20.5 trillion, however she did not fully explain where all that money would come from.

She insisted that the plan would not cost the middle class an extra penny, something Sanders has said is unrealistic.

“At the end of the day, the overwhelming majority of people will save money on their health care bills. But I do think it is appropriate to acknowledge that taxes will go up,” he said at the Democratic debate in October.

He added, “They’re going to go up significantly for the wealthy. And for virtually everybody, the tax increase they pay will be substantially less — substantially less than what they were paying for premiums and out-of-pocket expenses.”

Still, he has not specifically identified just how much taxes would increase.

“At the end of the day, we will pay for every nickel of Medicare for All, and it will save the overwhelming majority of the American people, who will no longer pay premiums,” Sanders told Harwood.