KABUL, Afghanistan — The collective wars in Afghanistan, Iraq and Syria have cost U.S. taxpayers more than $1.5 trillion since Sept. 11, 2001, according to a Defense Department report.

The current U.S. military operations, designated Operation Freedom's Sentinel in Afghanistan, Operation Inherent Resolve in Syria and Iraq, and Operation Noble Eagle for homeland security missions in the U.S. and Canada, have accounted for $185.5 billion of that sum.

Of the three current operations, Freedom Sentinel takes the lion's share of costs at $134.3 billion, followed by Noble Eagle at $27.7 billion, and Inherent Resolve at $23.5 billion. According to the report, the money goes toward training, equipment, maintenance as well as food, clothing, medical services and pay for troops.

Ahead of an announced trip to Afghanistan, Secretary of Defense James Mattis told reporters traveling with him that he was hopeful peace talks with the Taliban would signal an end to America's longest war. The fight in Afghanistan has been ongoing for the last 17 years.