The market, of course, is very, very happy. I wonder what the IMF terms were?

BRUSSELS — Global markets rallied Monday, reversing the steep declines of recent days, after European leaders agreed to provide a huge rescue package of nearly $1 trillion to combat the debt crisis that has engulfed Europe, and central banks began injecting cash into the financial system.

In an extraordinary meeting that lasted into the early hours of Monday morning, finance ministers from the European Union agreed on a deal that would provide $560 billion in new loans and $76 billion under an existing lending program to countries facing instability. Elena Salgado, the Spanish finance minister, who announced the deal, also said the International Monetary Fund was prepared to give up to $321 billion separately.

Officials were hoping the size of the program — a total of $957 billion — would signal a “shock and awe” commitment to such troubled countries as Greece, Portugal and Spain, in the same vein as the $700 billion package the United States government provided to help its own ailing financial institutions in 2008.

On top of the unprecedented sum, the European Central Bank reversed its position of just a few days ago and said it would buy government and corporate debt. And the world’s leading central banks, including the U.S. Federal Reserve, announced a joint intervention to make more dollars available for interbank lending.

Central bank purchases of euro-zone government bonds began Monday, although the E.C.B. did not immediately release details.