Ms. Hochul, a Democrat, unveiled the agreement just four days before the state budget is due in Albany, giving state lawmakers a relatively small window to scrutinize the details of the state portion of the financing that they must ultimately decide whether to approve.
The subsidy is bound to make the already fraught state budget negotiations even more contentious, with some left-wing Democrats from the downstate region already decrying the public funding as corporate welfare.
Indeed, the negotiations over a new stadium rekindled a bitter debate about whether government should be in the business of subsidizing arenas for professional sports teams; economic research has found that sports stadiums have rarely had a substantial impact, if any, on overall economic growth.
Public assistance, in the form of tax breaks and free land, has been used to finance the construction of arenas for New York sports teams, but many of the teams, from the Yankees to the Mets, have financed most of the costs themselves. The Giants and the Jets, which play in New Jersey, paid for nearly all of their stadium, which opened in 2010.
The negotiations also sparked skepticism about whether the Bills would have ultimately abandoned New York without a large government subsidy, though the owners never publicly threatened to uproot the team.
The Bills are owned by Pegula Sports and Entertainment, a company helmed by Terry and Kim Pegula, a wealthy couple based in Western New York; Mr. Pegula, who made his fortune through fracking, has a net worth of $5.8 billion, according to Forbes.
The new open-air stadium, which would be built across the street from the Bills’ current home in Orchard Park, a Buffalo suburb, would hold just over 60,000 fans, about 10,000 fewer than the current venue. But it would have a larger footprint overall and include about 60 box suites, a more lucrative source of revenue for teams.