Context

Cold War in the 1960s

Overview of Detente

Détente (a French word meaning release from tension) is the name given to a period of improved relations between the United States and the Soviet Union that began tentatively in 1971 and took decisive form when President Richard M. Nixon visited the secretary-general of the Soviet Communist party, Leonid I. Brezhnev, in Moscow, May 1972.

Read more at (and the above stolen from!) History.com

More detail:

Global Security – Cold War in the 1970s

CSU HSC Online – Detente

Office of the Historian (US Govt)
– Nuclear Non-Proliferation Treaty
– Strategic Arms Limitation Talks / Treaties (SALT I and II)
– Rapprochement with China (1972)
– Ending US Involvement in Vietnam

Foreign Affairs: Goodbye to Detente (1980)