WASHINGTON — President Barack Obama is sending Congress a $3.77 trillion spending blueprint that seeks to achieve an elusive “grand bargain” to tame runaway deficits by raising taxes further on the wealthy and trimming popular benefit programs such as Social Security.

The president’s proposal being unveiled today includes an additional $1.8 trillion in deficit reduction over the next decade, bringing total deficit savings to $4.3 trillion, based on the administration’s calculations.

It projects the deficit for the 2014 budget year, which begins Oct. 1, would fall to $744 billion. That would be the lowest gap between spending and revenue since 2008.

But instead of moving Congress nearer a grand bargain, Obama’s proposals so far have managed to anger both Republicans, who are upset by higher taxes, and Democrats upset with cuts to Social Security benefits.

The president’s spending and tax plan is two months late. The administration blames the delay on the lengthy “fiscal cliff” negotiations at the end of December and then fights over the March 1 automatic spending cuts.

The president’s plan tracks an offer he made to House Speaker John Boehner, R-Ohio, during December’s budget negotiations, which Boehner ended up walking away from because of his opposition to higher taxes on the wealthy.

The Obama budget proposal will join competing budget outlines already approved by the Republican-controlled House and the Democratic-run Senate.

Obama’s plan is not all about budget cuts. It also includes an additional $50 billion to fund infrastructure investments, including $40 billion in a “Fix It First” effort to provide immediate investments to repair highways, bridges, transit systems and airports nationwide.

Obama’s budget would also provide $1 billion to launch a network of 15 manufacturing innovation institutes across the country, and it earmarks funding to support high-speed rail projects.

The president also is proposing establishment of a program to offer preschool to all 4-year-olds from low- and moderate-income families, with the money to support the effort coming from increased taxes on tobacco products.

The administration said its proposals to increase spending would not increase the deficit but rather are paid for either by increasing taxes or making deeper cuts to other programs.

Among the proposed cuts, the administration wants to trim defense spending by an additional $100 billion and domestic programs by an extra $100 billion over the next decade.