Do I need any document so other than my round trip ticket and my Canadian passport?

I am a Canadian citizen (hold a Canadian passport) and will be flying out of Detroit Michigan (DTW) Oct 15 and landing in Beijing (PEK) on Oct 16 en route to Hong Kong. My flight to Hong Kong leaves 3 hours later (Air China) and I do not intend to leave the airport. I return from Hong Kong, to Detroit, landing again for 3 hours in Beijing on Oct 22. I will not leave the airport at this time either. Do I need any documents beside my round trip air tickets and my passport?