[muawiyah]

While working at USPS employees pay into a retirement fund ~ as does USPS on their behalf. Their pensions are 100% funded.

Other federal pensions are not.

USPS could collapse and go out of business and that would not affect postal pensions.

[DManA]

Fully funded assuming the administrators earn 8%/year return on funds, and assuming Uncle stupid stands ready to make up any deficit.