The Obama administration has yet to specify how long U.S. troops might actually remain in Afghanistan to complete their training and support mission, and the agreement extends far past Obama's tenure as president.
U.S. officials have not yet disclosed the number of U.S. troops they want to keep in Afghanistan after 2014.
U.S. officials have said the U.S. and NATO could keep between 8,000 and 12,000 troops there.
Of those, the U.S. is expected to provide no more than 8,000.