"Fifty years ago, the Cuban missile crisis brought the world to the brink of nuclear disaster. During the standoff, US President John F. Kennedy thought the chance of escalation to war was "between 1 in 3 and even," and what we have learned in later decades has done nothing to lengthen those odds. We now know, for example, that in addition to nuclear-armed ballistic missiles, the Soviet Union had deployed 100 tactical nuclear weapons to Cuba, and the local Soviet commander there could have launched these weapons without additional codes or commands from Moscow. The US air strike and invasion that were scheduled for the third week of the confrontation would likely have triggered a nuclear response against American ships and troops, and perhaps even Miami. The resulting war might have led to the deaths of 100 million Americans and over 100 million Russians."
That's the only estimate I've ever seen that says that the damage the Soviets could have inflicted on the US was anything like as severe as what the US has planned for the Soviets. Of course, the US could have faced a lot of damage, but nothing like the complete annihilation that would have been visited on the Soviets and other socialist countries.
The US consistently over-estimated the strategic threat the Soviets posed to the US for most of the Cold War - particularly the infamous "Bomber Gap" and the "Missile Gap":
https://en.wikipedia.org/wiki/Cuban_Missile_Crisis#Post-cris...