He told senators so on Thursday.
"When can you start?" said one appreciative lawmaker, Sen. Mark Dayton, D-Minn.
The United Nations says it will cost $1.2 billion to overhaul the 39-story building along New York's East River. No, says the city's highest-profile developer. More like $3 billion, he told senators.
This project is no more challenging, he said, when he refurbished the skating rink in Central Park. That was years ago, when New York could not.
"This is a bigger version of the Wollman Skating Rink, that's all it is to me. ... I don't want any money. I want nothing," said the star of NBC's "The Apprentice" and author of "Trump: The Art of the Deal."
Trump's estimate for the work: $600 million to $700 million. He appealed to members of a Senate Homeland Security and Governmental Affairs subcommittee to let him do it. He would manage the project, and waive his fee.
Besides, he knows what it takes to get things built in Manhattan and U.N. types don't, he said.
"They don't know what they want, they don't know what they have, they don't know what they're doing," Trump said.