WASHINGTON (AP) -- The House on Wednesday took up a wide-ranging tax bill including more than $50 billion in incentives to promote renewable energy sources and financial relief for millions of parents, teachers, homeowners and businesses.

The package extends dozens of narrowly focused tax breaks, such as deductions for state and local general sales taxes, that have expired or are about to expire, while expanding the child tax credit and creating a new deduction for property taxes.

The tax measures are generally popular and non-controversial, but the bill is shadowed by a fundamental difference -- between Democrats and Republicans and the House and Senate -- over whether the $54 billion in tax relief should be offset by an equivalent amount of new revenues.

House Democrats, following their "pay-as-you-go" rules, would pay for the bill by closing loopholes involving corporations with offshore offices. Republicans, meanwhile, object to what they say are new taxes and complain that the bill fails to address the issue of the alternative minimum tax, which could hit more than 20 million additional taxpayers this year, at a cost of more than $2,000 a family, if Congress doesn't act.

The White House, voicing opposition to the new tax revenues and the lack of AMT relief, threatened a veto.

The AMT was created in 1969 to catch a small number of very rich tax dodgers, but was not adjusted for inflation. As a result, every year, without a congressional fix, catches more upper-middle-class taxpayers. Last year Congress battled into December, delaying the processing of some IRS returns, over whether to pay for a $50 billion AMT fix. In the end there was no offset.

The tax break extensions include deductions for tuition and other education expenses, deductions for the out-of-pocket expenses of teachers, deductions of property taxes for non-itemizers and permits for tax-free charitable contributions from individual retirement accounts.

It would increase eligibility for the refundable tax credit in 2008. That's the credit that becomes available when the child tax credit, worth up to $1,000 per child, exceeds a person's tax liability. The measure would extend the credit to 12 million more children.

Another provision, costing an estimated $1.6 billion over 10 years, would give a more generous deduction to attorneys who pay litigation costs in advance in contingency-fee cases.

The bill would extend the research and development credit, at a cost of about $8.8 billion over 10 years, while providing some $17 billion in tax incentives for renewable energy sources such as wind and solar power and carbon capture and sequestration projects.