What countries does the free world refer to?

Capitalist countries such as the United States and Britain. Truman Doctrine originated from the Cold War. 1947 March 12, President Truman delivered a speech in Congress, claiming that in order to prevent the infiltration of capitalism, the United States has the mission of leading the free world and assisting the revival of some countries, emphasizing the necessity of assisting Greece and Turkey, believing that this actually involves the struggle between two social systems. The free world he said is a complete capitalist system and a hegemonic thought.