WASHINGTON -- Democrats at both ends of the Capitol accelerated their drive to enact health-care legislation Tuesday, outlining proposals to extend coverage to uninsured millions but omitting most details on plans for raising more than $1 trillion needed to cover costs.

"We are going to be deficit-neutral -- even -- over five or 10 years," White House budget director Peter Orszag said, and President Obama told Democratic lawmakers he would soon outline as much as $300 billion in additional savings from Medicare and Medicaid.

A first-ever tax on employer-provided health benefits also figures among options under consideration in Congress, but Obama campaigned against that last year and its inclusion in the bill would require him to reverse course.

Given the uncertainty as well as the political sensitivity over raising taxes or cutting Medicare, Senate Republicans want Democrats to fill in the blanks before the scheduled beginning of committee work next week.

At their core, a partial draft bill released by Democrats on the Senate Health, Education, Labor and Pensions Committee and an outline circulated by House Democrats were largely the same.

Individuals would be able to buy insurance through a new federally regulated national exchange, and private companies would be barred from denying coverage or charging higher premiums because of pre-existing conditions.

Both bills would require individuals to purchase insurance if they could afford it. Waivers would be available in hardship cases. The Senate measure provides for an unspecified penalty for anyone refusing to obey the so-called mandate, and House Democrats are considering a similar approach.

The emerging House plan would also give individuals the option of buying insurance provided by the federal government.

Democrats on the Senate committee embraced a similar provision last week, but omitted it from the draft released Tuesday in what Sen. Chris Dodd, D-Conn., said was a gesture to Republicans who oppose it.

Sen. Mike Enzi, R-Wyo., the top Republican on the health committee, said Democrats did so "because they know we're not going to like what they've written and they don't want us to have any time to comment."

His remarks were not the only evidence of partisan maneuvering during the day, suggesting the White House's goal of a bipartisan bill was growing more distant.

Senate Republicans on two committees involved with health care urged Democrats not to move ahead without detailed cost information. "Paying for health reform in a responsible and sustainable way may be the most single difficult element of our efforts," they wrote.

But after months of preliminary effort, Democrats made clear they intend to move ahead on their own timetable, one that calls for passage of legislation in the House and Senate by early August. A final compromise would wait for September or later in the fall, according to a schedule the party's leadership established weeks ago.

"This is the year we have to do it," said Rep. Henry Waxman, the California Democrat who chairs the House Energy and Commerce Committee. Waxman was one of several senior Democrats who outlined proposed legislation to the party's rank and file during the day.

Numerous senior Democrats now aging and ailing have worked their entire careers on health care, but no one is more identified with the issue than Sen. Edward M. Kennedy, the Massachusetts Democrat first elected to the Senate in 1964. But in a poignant announcement during the day, Dodd said Kennedy, diagnosed a year ago with a brain tumor, will be unable to attend the working sessions of the health committee he chairs beginning next week.

Obama has made an overhaul of the health care system a top priority of his first year in office, both to assure coverage for the uninsured and also to slow the rate of growth in health care nationally. Outside groups representing hospitals, doctors, drug companies and others have pledged to work with the White House on that objective, but it is not clear how much money their efforts would yield in savings to the government.

That leaves lawmakers with the difficult chore of agreeing on a series of tax increases and spending reductions if they are to cover the costs of the legislation.

Obama met with a group of House Democrats at the White House during the day, and Orszag said the discussion centered on the administration's recent announcement that it is willing to try to find as much as $600 billion in Medicare savings, double what the president requested in his budget last winter.

"What I want to be very clear about is, at worst this will be deficit-neutral," the president said. "And then to the extent that these changes succeed in altering the practice of medicine in the way that experts have long believed that they will, the result will be much better than that."

In both the House and Senate, Democrats want to provide subsidies to families with incomes of up to about $88,000 a year to help them pay for insurance.

House Democrats also are considering a wide-ranging change for Medicaid that would provide a uniform benefit across all 50 states and increase payments to providers, according to several officials. Medicaid is a joint state-federal program of health coverage for the poor.

The measure also envisions several changes to Medicare, the government program that provides health care to seniors, although details are lacking.

According to the outline, the gap between primary care physician fees and those of specialists would be narrowed, and beneficiaries would not incur out-of-pocket costs for preventive services. The outline also mentions unspecified improvements in the prescription drug benefit. Democrats vociferously opposed that benefit when Republicans passed it, saying it provided billions in unnecessary subsidies to pharmaceutical companies.

Part of the cost would be covered in the form of cuts in the government payments under Medicare plans run by private insurance companies, which receive more per patient than the cost of traditional coverage.

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Associated Press writers Ricardo Alonso-Zaldivar and Erica Werner contributed to this report.