
Travel Document Requirements
U.S. citizens traveling to the U.S. must have a valid, unexpired U.S. passport. However, U.S. citizen military personnel may be boarded without a U.S. passport if in possession of official travel orders AND either
is in possession of valid military ID; or
is wearing a U.S. military uniform.
U.S. Citizen Merchant Mariners
U.S. citizen Merchant Mariners may be boarded without a U.S. passport if in possession of U.S. Merchant Marine card indicating U.S. citizenship. 

Overview
Renewal: