Conversation so far:
What was Henry Kissinger's détente?
Détente was the policy of relaxing tensions between Moscow and the West, as promoted by Richard Nixon, Henry Kissinger and Leonid Brezhnev.
What was the détente policy about?
Henry Kissinger's policy détente is the easing of strained relations, especially in a political situation, through verbal communication.

Question: Was it successful?
Self-contained rewrite: Was Henry Kissinger's détente policy successful?