There is no universal answer. Buut the difference will be so small as to be incalculable…unless you’re driving a Bugatti Veyron. Or perhaps an Escallade.
However, unless your vehicle is designed for the engine to be shut off and restarted repeatedly, as some vehicles do automatically, you’ll prematurely wear out your starter motor.
By the way, those vehicles that aree designed to partially shut off the fuel supply don’t use inertial energy to keep running, the use the cylinders that they did NOT shut off to keep running. It really take little energy to keep a moder engine running at idle. The gas used ins miniscule. Today’s torque converters are so adept at dissipating the energy from an idling engine that they put no drag on the crank. Many will even roll backwards a bit if you take your foot off the gas while on an incline.
Engines that shut down completely when you stop are in hybrinds and use the stored energy in the battery packs to keep everything enabled and ready.