Meanwhile, a new estimate says the wars in Iraq and Afghanistan could cost upwards of $2.4 trillion over the next decade. The Congressional Budget Office says the figure takes into account more than $700 billion in interest since the wars are being funded with borrowed money. The total amounts to nearly $8,000 for every U.S. resident. The Iraq war accounts for roughly 80 percent, at $1.9 trillion. In the lead-up to the Iraq war four years ago, the Bush administration estimated the invasion would cost no more than $50 billion.