Double Transit Stop in China

Hello,
I'm a US national who will be traveling from Kota Kinabalu, Malaysia to the US. I'm flying through Guangzhou and Beijing within a 24 hour period. In Guangzhou, I switch from Air Asia to Hainan Airlines. Hainan will be my carrier until I reach the US. From all I've read, it does not appear I'll need a visa, but I would feel far more at ease if someone could confirm this is the case.

Thank you.