In response to the recently announced 2020 Social Security Payroll Tax Deferral, the Defense Finance and Accounting Service (DFAS) published a website https://www.dfas.mil/taxes/Social-Security-Deferral/  to inform and help prepare Service members and DoD Civilian employees regarding temporary changes they may experience in their net take home.  The website is the primary source for answers to frequently asked questions, policy, and  guidance and will be updated regularly as new information becomes available. They have also come out with 3 resources to help explain.

Payroll_Fact_Sheet_Civilian_Payroll_(9 SEP) FINAL Payroll_Fact_Sheet_Military_Payroll_(9 SEP) FINAL
200908 -Tax Deferral Briefing Card – FINAL