ESPN.com confirmed that the figure announced by the Greek government was almost double the original estimate, making the Games easily the most expensive in Olympic history.
The 2000 Sydney Games cost $1.5billion and the 1996 Atlanta Games $1.72billion.
The last official estimate came in mid-August, when Greek secretary of state for finance, Petros Doukas, announced a figure of $9billion.
"This is the immediate cost for the state and does not include expenditures for infrastructure," finance minister Giorgos Alogoskoufis said after a Cabinet meeting. He did not give a figure for the infrastructure costs.
Those costs include expensive transportation projects such as a new tram line, suburban rail network and the extension of the Athens metro system to the airport. Built in 2004, the tram alone cost at least $344million.
"There is a huge overrun in relation to original estimates," Alogoskoufis said.
The government also has not said what it will do with more than $2.83billion in new or refurbished sports venues.
A recent government study predicted it will take $103.8million a year for the maintenance and operation of Olympic sites, including the main stadium complex.
The figures - released on Friday for the first time - included the budget of the Athens Organising Committee (ATHOC) that until recently had been handled as a separate account.
The government’s early estimate for infrastructure and venue construction was about $5billion.
Officials from Athens 2004 would not confirm the amount of profit they are expecting to produce.
But aroundtherings.com reported last week that the Games may still turn into a profit for ATHOC.
A privately-funded company, ATHOC received its income from TV rights fees, sponsorships, tickets and licensed product sales.
