WASHINGTON  The Federal Reserve disclosed on Wednesday that its chief policy makers were divided on whether the weak economy faced a new, potentially dangerous threat in the form of deflation.

The dissent within the Fed emerged as the White House released a report estimating that its economic stimulus program had saved or created 2.5 million to 3.6 million jobs since it was enacted, over nearly unanimous Republican opposition, at the start of President Obama’s term.

The estimates in the report were in line with those of the nonpartisan Congressional Budget Office and independent experts. But Senate Republicans, who have blocked legislation to extend unemployment benefits, continued to portray the administration as fiscally reckless and the stimulus as ineffective.

“I know what they’re against, but I don’t know what they’re for,” Vice President Joseph R. Biden Jr. said of the Republicans as he unveiled the report. “I mean that literally.”