Is power CABLE from MacBook compatible with MacBook Pro?

I have an older 2015 MacBook. I just bought a new 2018 MacBook Pro (13-inch). Can I use the original USB-C cable (not power adapter) with the new MacBook Pro and its larger power adapter. When I take the MacBook cable and place it beside my MacBook Pro cable, the MacBook one is very slightly thinner in diameter. Since the MacBook Pro draws more power, I want to make sure it is safe to use the cable from the MacBook to charge my MacBook Pro with its larger power adapter.