The Apple 15" MacBook Pro (Late 2016) is provided with its own Apple 87W USB-C Power Adapter for optimal charging over the USB Type-C connector. With that, we shall see how fast the Apple 87W USB-C Power Adapter charges the Mac using the software from Granite River Labs.
The software shows that the Mac accepts the initial 12 watts (5 volts @ 2.4 amps) provided by the Apple 87W USB-C Power Adapter.
When the Apple 87W USB-C Power Adapter later declares it can supply additional 27 watts (9 volts @ 3 amps) and 86 watts (20 volts @ 4.3 amps), the Apple 15" MacBook Pro (Late 2016) chooses to accept 86 watts (20 volts @ 4.3 amps).
From the oscilloscope screenshot, we can actually see that the Mac pulls around 18 volts @ 0.6 amps from the Apple 87W USB-C Power Adapter on a full charge.
As to be expected, the Apple 87W USB-C Power Adapter works well with the Apple 15" MacBook Pro (Late 2016) through USB Power Delivery Technology. USB Power Delivery also now allows non-Apple charging sources to power the new Apple 15" MacBook Pro (Late 2016).