Detente was the word used to describe a reduction in hostility between the Soviet Union and the US.
At a time where every waking moment was spent in fear of missiles, atomic bombs, and invasion, there was a dire need for some sort of reassurance that each of the super powers would be relatively safe.
Detente didn't call for an ending to the war, however it did call for temporary "peace". Neither was willing to come to one conclusion on the right way to run their respected nation, but they decided to work together on projects to, basically, distract their people.
This was an official meeting which called for a "Strategic Arms Limitation Talk" (SALT). It was basically an armistice.
After this big step, the two super powers were able to embark on a motley of programs to better their country in various ways.
Maybe the most notorious of all the programs the two nations worked together on, is the extreme advancement in space research and technology.
The end of Detente
Even though the two nations were attempting to cease the violence, it was obvious that this close contact was only going to escalate the issues at hand.
A very important reason for the split was the relationship of America and China. During "detente" the US agreed to sell weapons to the Chinese military. China and the Soviets had past disputes and this interaction between the two nations was viewed as disrespectful by the Soviet
The other big reason for the split was the Soviet invasion of Afghanistan. This broke the "SALT" agreement that the two super powers held.
The obvious effect of Detente was the decline of both super powers. The Soviet Union has diminished to nothing, while many believe the US is on the fast decline. Both nations have less influence around the world than they once did.