The lack of specifics in Mr. Trump’s plans was also a problem for the Congressional Budget Office. It said that in many cases where Mr. Trump’s policy initiatives lacked details, its analysts had to use place-holder figures.

The $4.1 trillion budget for 2018 that the White House proposed recommended a large increase in spending on the military and on border security. By assuming rapidly accelerating economic growth, Mr. Trump’s economic team was able to make the budget balance without making changes to Social Security’s retirement program or Medicare, the two biggest drivers of America’s federal government debt.

Tepid economic growth and an aging population have raised concerns about the future of those programs. The Trump administration said Thursday that the financial outlook for Medicare’s Hospital Insurance Trust Fund had slightly improved in the last year but that Social Security still faced serious long-term financial problems.

The Medicare trust fund will be depleted in 2029, the administration said. Last year the government said that the trust fund would be exhausted in 2028.

In a companion report, federal officials said the Social Security Trust Funds for old-age benefits and disability insurance could be depleted in 2034. Last year’s report also said that the combined trust funds would be depleted in 2034, but that tax collections would still be sufficient to pay about three-quarters of promised benefits for a half-century more.