Bush administration seeks to downplay report due for release next week.
Funding for conflicts in Iraq and Afghanistan guaranteed beyond US president’s term.
The bill means that congress has so far approved $650bn to be spent on the Iraq war since it began more than five years ago.
Another almost $200bn has been spent on operations in Afghanistan so far, congressional officials say.
“Our nation has no greater responsibility than to support our men in women in uniform – especially because we’re at war,” Bush said.
College benefits for troops and veterans will be doubled as part of the new funding package.
It also provides for a 13-week extension of unemployment benefits and $2.7bn in emergency flood relief for the US Midwest.