In a new policy layout set to be unveiled Monday, Donald Trump’s economic proposal will promote one of the biggest tax cuts since Ronald Reagan’s presidency, an advisor to the Republican Presidential nominee told Bloomberg Politics.

The proposal will reiterate Trump’s plan to cut the corporate tax rate to 15%. Stephen Moore, the chief economist for the Heritage Foundation, and of one of the men on Trump’s 13-member economic advisory team that the Republican presidential candidate announced Friday, revealed the plan has some slight adaptations.

Although he did not specify a timeline or said adaptations, Trump has managed to whittle down the cost in terms of lost tax revenue by about two-thirds, to $3 trillion, Moore said.

Trump’s promised new policy agenda for “revitalizing the American economy”will be the theme of his speech Monday at the Detroit Economic Club. Again, his tax cut will be the largest in history since the Reagan administration tax cut.