The US has revealed that it has spent $43.5bn (£21bn) on intelligence during 2007, the first time the figure has been made public in almost a decade.
Mike McConnell fears risking US security if too much is revealed
Intelligence chief Mike McConnell said he would give no breakdown of how the money was spent, saying that disclosure could harm national security.
The disclosure was made to comply with a law passed by Congress last year.
The 2007 sum, split among 16 agencies, is almost double what was spent in 1997 and 1998, the last budgets made public.
According to legislation signed into law by US President George W Bush, total intelligence spending must be revealed 30 days after the end of the fiscal year, on 30 September.
Exactly where the money goes remains classified, but a share will go on salaries for an estimated 100,000 people, among them intelligence analysts and spies, the Associated Press reports.
Also covered will be such expenses as high-tech secret satellite programmes, aircraft, weapons, computers and software.
The budget includes money for the CIA, the Defence Intelligence Agency, the National Security Agency and FBI intelligence programmes, as well as agencies within the state and treasury departments.
The figure does not include what is spent by the US military on gathering intelligence.
Mr McConnell, releasing a brief statement highlighting the main figure, made it clear he did not intend to give more details.
"Any and all information concerning the intelligence budget, whether the information concerns particular intelligence agencies or particular intelligence programmes, will not be disclosed," he said.
Intelligence officials have argued that detailed figures could be used by others to track fluctuations in spending and so ascertain information about secret intelligence schemes.
Former CIA director George Tenet released the budget figures for 1997 ($26.6bn) and 1998 ($26.7bn), saying he saw no risk to national security in doing so.
Intelligence spending increased significantly after the 11 September, 2001, terror attacks on the US.
The 2007 figure is greater than the national economies of all but the world's 60 or so richest nations.