BP has announced third-quarter losses of $16.9bn, after making $32.2bn available for the clean-up operation following the Gulf of Mexico oil spill.
It is the first time the company has gone into the red for 18 years.
It posted the loss for the months between April and June following the Deepwater Horizon disaster.
The firm also announced a shake-up of its portfolio, including up to $30bn in asset sales over the next 18 months.
The company has so far amassed a huge bill for the oil spill.
Approximately 1026km of Gulf coast is officially listed as 'oiled', in Louisiana, 175km in Mississippi, 112km in Alabama, and 156km in Florida.
The beaches should be relatively easy to mop up, but cleaning up the maze of marshes, where there is nothing to stand on and shallow-bottomed boats are needed to navigate the narrow channels, is a logistical nightmare.
BP has also confirmed that chief executive Tony Hayward will step down in October.
Mr Hayward, who has been criticised for his handling of the Gulf of Mexico oil spill, is to be replaced by senior US executive Bob Dudley.
Mr Dudley is currently overseeing the company's response to the disaster.
Meanwhile, BP could begin the final procedure to stop its leaking well late next week, the top US spill response official said.
Watch live feeds of the operation
That will involve pumping mud and cement through a relief well that has been drilled since 2 May to a spot close to the bottom of the damaged well.
'The next thing that we need to do is get this well in the position where we can make the intercept and kill this well from the bottom,' retired Coast Guard Admiral Thad Allen said.
More than 5m barrels of oil have spilled into the Gulf of Mexico since the undersea leak began in late April, according to US government estimates.
The disaster has hit the coastlines and economies of five states and killed or injured countless sea creatures and coastal birds.
