The Marshall Plan was one of many aid and loan programs that the United States implemented to help Europe recover from the destruction wrought by nearly seven years of fighting. Though the US, and her neighbor to the north Canada, implemented many programs, the Marshall Plan is the most well known. All told, Western Europe received over 12.7 billion dollars in aid from the Marshall Program. Today it would be the equivalent of a 120 billion dollars, and at the time was almost 4% of US GDP during that period. In other words, it was mid-century version of the stimulus bill, which was around 5% of GDP, that was sent to foreign nations. Factoring Canada's aid and the other unmentioned loans and programs to help Europe, the nations of Europe received hundreds of billions of inflation adjusted dollars.
This is interesting, because contrary to what many of us in the west think, it appears that the plague of European socialism was not first implemented by communists or socialists within Europe but by the United States herself; though one could make an argument that the Marshall Plan was a covert operation by communist agents/sympathizers within the US but it must also be noted that Stalin was very hostile to the plan. The Marshall Plan was a great success, in a geopolitical sense, for America because it helped quell the growing communist movements within the western nations and western European nations loved the program because it allowed them to ease off from austerity because the US artificially boosted spending, a perfect Keynesian policy. Though some argue that the Marshall Plan only accelerated, but did not cause, the twenty year long economic boom; it isn't hard to see how this program, coupled with the ever present US defense umbrella, sowed the seeds for democratic socialism a few decades later.