Brightest light in sky, round white light that moved consistently, made no sound, then suddenly disappeared.

Looking at the night sky to observe the ISS, which we saw. We also saw several aircraft that appeared to be commercial jets. Shortly after seeing the ISS, we saw a very bright white light moving NW to SE. It was a round or spherical shape and was the brightest light in the sky. There were no flashing lights like an aircraft, and it made no sound. After watching for approximately 15-20 seconds, it disappeared. It did not fly away at high speed. It was not cloudy and didn’t appear to fly behind a cloud. Just there, very bright one second, and gone the next.