Read the article! The operational losses EXCLUDE the pension obligations!
The Post Office is RUNNING AT A LOSS, YEAR AFTER YEAR.
Why does the USPS still have a monopoly at all, if they are insolvent?
As i said ask your congresscritter ~ but the pension obligations have to do with the ordinary payments being made by the agency to OPM for FERS and CSRS ~ the other losses consist primarily of depreciation ~ if you'd take a really good look at the annual report and not the 'article' ~ at the same time the Congress has refused to grant them the authority to close down unnecessary facilities and to lay off unnecessary employees.
That means CONGRESS, not USPS, is insolvent if anyone is. The USPS is still a wholly owned independent executive establishment of the US government.