House Republicans have unveiled the first details in their sweeping bill to implement President Donald Trump’s agenda, promising to pump in roughly $150 billion for defense programs and tens of billions more in border security measures.

WASHINGTON—Republicans pushed President Trump’s “big, beautiful” tax and spending package closer to the finish line with votes earlier this month approving a budget framework. But as lawmakers return to work this week, hard intraparty fights remain in writing and ironing out the multitrillion-dollar package.