If you believed him, then you were an idiot…

Newly obtained tax information reveals that from 1985 to 1994, Donald J. Trump’s businesses were in far bleaker condition than was previously known.

By the time his master-of-the-universe memoir “Trump: The Art of the Deal” hit bookstores in 1987, Donald J. Trump was already in deep financial distress, losing tens of millions of dollars on troubled business deals, according to previously unrevealed figures from his federal income tax returns.

Mr. Trump was propelled to the presidency, in part, by a self-spun narrative of business success and of setbacks triumphantly overcome. He has attributed his first run of reversals and bankruptcies to the recession that took hold in 1990. But 10 years of tax information obtained by The New York Times paints a different, and far bleaker, picture of his deal-making abilities and financial condition.

The data — printouts from Mr. Trump’s official Internal Revenue Service tax transcripts, with the figures from his federal tax form, the 1040, for the years 1985 to 1994 — represents the fullest and most detailed look to date at the president’s taxes, information he has kept from public view. Though the information does not cover the tax years at the center of an escalating battle between the Trump administration and Congress, it traces the most tumultuous chapter in a long business career — an era of fevered acquisition and spectacular collapse.

The numbers show that in 1985, Mr. Trump reported losses of $46.1 million from his core businesses — largely casinos, hotels and retail space in apartment buildings. They continued to lose money every year, totaling $1.17 billion in losses for the decade.

In fact, year after year, Mr. Trump appears to have lost more money than nearly any other individual American taxpayer, The Times found when it compared his results with detailed information the I.R.S. compiles on an annual sampling of high-income earners. His core business losses in 1990 and 1991 — more than $250 million each year — were more than double those of the nearest taxpayers in the I.R.S. information for those years.

Over all, Mr. Trump lost so much money that he was able to avoid paying income taxes for eight of the 10 years. It is not known whether the I.R.S. later required changes after audits.