Air carrier Captain reported having to stop abruptly on the taxiway at ORD to avoid a collision with a wide body aircraft.

Narrative

While taxiing northwest on Taxiway Q; where Q transitions into Taxiway G; I observed a Commercial Aircraft taxiing northbound on either Taxilane B or C. As the Commercial Aircraft attempted to turn southwest onto Taxiway U; it swung the turn too wide.Recognizing the potential conflict; I stopped my aircraft and issued two instructions to the Commercial Aircraft to stop via ground frequency. The Commercial aircraft did not acknowledge either call.As a result; the Commercial Aircraft wingtip passed over my aircraft's wingtip by just a few feet. Had I not stopped; a collision would likely have occurred.We immediately contacted ground control; who advised us to call the ground supervisor. A full debrief of the situation was conducted.Cause: The Commercial Aircraft either missed their turn or initiated the turn too wide; demonstrating no apparent situational awareness of my aircraft's position. They were on the outbound ground frequency at the time and did not hear or respond to my repeated calls to stop.