President Trump signed what he termed a “breakthrough” executive order requiring hospitals to inform patients of the prices they hash out with insurers.

“We should also require drug companies, insurance companies, and hospitals to disclose real prices to foster competition and bring costs down,” Trump said in announcing the administration’s latest move to combat the nation’s spiraling healthcare costs.

The new order instructs HHS to issue a rule requiring healthcare providers to tell patients their out-of-pocket costs prior to receiving services. The exact regulatory details—such as the level of depth that will be required of hospitals—will be spelled out in the proposed rulemaking.

HHS Secretary Alex Azar called the order “one of the most significant steps in the long history of American healthcare reform.”