DETROIT — In one of the largest buyout programs ever, more than 125,000 hourly workers of General Motors Corp. and auto supplier Delphi Corp. are being offered up to $140,000 to give up their jobs to help cut the companies' crippling labor costs.

GM did not say how many workers it expected to accept the offer, but it is aiming to slash 30,000 hourly jobs by 2008.

Some workers wasted no time in declaring the deal "fantastic" and started calculating what they would get, based on years of service, if they accepted the offer.

GM and Delphi have said that if enough workers sign up for buyouts or early retirement, their operating costs would drop significantly. Analysts warned that it still might not be enough to restore the companies' financial health or avoid a paralyzing strike.

Under the program, about 113,000 GM workers will be eligible for early retirement incentives or buyouts of between $35,000 and $140,000 depending on how long they were employed and whether they want to keep healthcare and other benefits. At Delphi, GM's former parts division and largest supplier, 13,000 U.S. hourly workers will be eligible for a lump sum payment of $35,000 to retire. Also, up to 5,000 Delphi workers will be eligible to return to GM.

The deal comes at a critical time for GM, which last week increased by $2 billion its reported 2005 loss to $10.6 billion. The world's largest automaker has been losing U.S. market share to Asian automakers and is saddled with labor agreements that make it difficult to close plants or cut workers. The plan also is crucial for Delphi, the largest U.S. auto parts supplier, which is reorganizing in bankruptcy court after filing for Chapter 11 protection in October.

The companies made no predictions of how many employees might accept the offers or exactly how much they would save in operating costs. GM has a goal of cutting 30,000 hourly jobs by 2008.

David Cole, chairman of the Center for Automotive Research and the son of a former GM president, said the deal is of historic proportions.

"It's huge — far more than I expected," Cole said. He said the deal could go a long way toward helping GM return to profitability and to speeding Delphi's exit from bankruptcy. Cole said he expects many workers will take the buyout.

"For our members, this is fantastic," said Dan Fairbanks, president of United Auto Workers Local 1618 in Lansing. "There's some huge incentives here."

Michael Balls, 49, a pipefitter at the Delphi steering systems plant in Saginaw, was more cautious about his own options after reading details of the agreement.

"I feel a lot better, but I'm still questionable about some things," said Balls, who with 30 years of service is eligible to retire and would get $35,000. He said he might take the offer — or might return to GM if they will offer him a skilled trades job.

Under the plan, GM would pay for the Delphi early retirement incentives and assume some post-retirement benefits for Delphi employees who go back to work for GM. GM spokesman Dan Flores said GM didn't yet know the full cost of the plans, since it's unclear how many workers will participate.

Himanshu Patel, an auto analyst with JPMorgan, said GM will likely pay around $2 billion for the Delphi buyouts based on recent financial filings, while Merrill Lynch analyst John Murphy said GM will probably pay "well in excess of $1 billion" for its own buyouts.

Several analysts questioned how much GM and Delphi will save. Most workers who retire will get full benefits, which doesn't relieve GM's sizable pension obligations, Goldman Sachs analyst Robert Barry said in a note to investors. Barry added that savings gained from the retirement of younger workers will be offset by GM's assumption of Delphi retiree benefits.

GM shares rose a penny to close at $22.01 on the New York Stock Exchange.