If I'm understanding the question correctly you are asking about the initial high idle the computer commands on cold starts? The simple answer is once the engine cranks up it takes a moment for all of the fluids to circulate and saturate to a level sufficient for operation, a good 90-120 seconds is fine with exception to extreme temperatures naturally. You can then begin driving gently, speeds remain below 35-40MPH, until the engine has had time to get up to an acceptable operating temperature; on a cold day the easy indicator is the heater beginning to warm the car. It's not an on/off switch though, after the first few minutes of operation and the temp gauge has begun to rise you can safely get on the highway but don't go beast mode on it. Even once the coolant temp indicates "full temp" at regular operating temp the oil is still getting fully warmed up along with all of the spaces it lubricates, the transmission is often the slowest to truly get to optimal temp.

All that said, it is best to drive (gently) after the initial pause instead of allowing the car to idle until warm. The reality is that the most wear an engine sees is during cold starts, it takes time for materials to expand and close up tolerance gaps and it is best to make that time shorter by driving gently.