Department of Defense Instruction 1300.17: Accommodation of Religious Practices Within the Military Services, February 10, 2009 [Incorporating Change 1, January 22, 2014] [open pdf - 85KB]
"It is DoD policy that: The DoD places a high value on the rights of members of the Military Services to observe the tenets of their respective religions or to observe no religion at all. It protects the civil liberties of its personnel and the public to the greatest extent possible, consistent with its military requirements, in accordance with DoD Instruction (DoDI) 1000.29 (Reference (c))."
Department of Defense Instruction 1300.17; DoDI 1300.17
Defense Technical Information Center: http://www.dtic.mil/