Which document contained the original idea for the League of Nations?

The original idea for the League of Nations was articulated in U.S. President Woodrow Wilson's Fourteen Points speech delivered on January 8, 1918. In this address, Wilson proposed the establishment of a general association of nations to ensure peace and cooperation among countries. This concept was later formalized in the Treaty of Versailles, signed in 1919, which established the League as a means to prevent future conflicts.