Federal full-time equivalent civilian employees: 1.8 million
Federal uniformed military personnel: 1.5 million
U.S. postal workers: 0.85 million
Federal grant-created jobs: 2.4 million
State and local mandate-created jobs: 4.7 million
Federal contract-created jobs: 5.6 million
source:GovExec.com January 1999
If you count postal workers it comes pretty close to your number. Postal workers usually aren't counted because they are a government enterprise and are theoretically self-supported (which they are for the most part, the government induced monopoly is the real issue with them). Notice the number of contractors and State and local mandates jobs. That's where the "growth" in the federal work force has really taken place.
Part of the military decrease is the Rumsfield policy to move support jobs (clerks, mechanics, cooks, etc.) to civilian or contractors and make more of the military direct fighters and not support clerks. Actually following the Marine model in all Marines are infantry first.