White Smoke while Jeep is either idling or not moving.

The Jeep is fine while running. No smoke ever gets put out from the exhaust while running but when I happen to stop for about 3 minutes or more, like for example at a drive thru, it sometimes puts out white smoke. Also when I idle it for 5 minutes or longer. The Smoke smells like partially used gas as if the Jeep is still trying to use gas when it doesnt need it. Why is this? The engine is strong and the transmission still feels great! Point me in a direction.