The alliance in which the United States were included and which promoted their interests and their protection was the NATO.
The alliance in which the Soviet Union was included and which promoted their interests and their protection was the Warsaw Pact.
These two organizations were primarily military organization. They had to purpose of securing their interests and protection from their rivals.
NATO was consisted of the USA, UK, France, Australia, Canada, pretty much the so called Western countries.
The Warsaw Pact was consisted of the USSR and all of the Eastern European fellow communist countries.