The Apple Watch is probably a rounding error when compared to the iPhone, however:

"But the most interesting stuff came when Cook referred to the success of Apple Watch. The Watch sales are part of the wearables business which also includes headphones such as Beats and AirPods.

Last May, he said that business is approaching the size of a Fortune 500 company. More recently, last month, the size had crept up so it would fall in the top 400"

https://www.forbes.com/sites/davidphelan/2018/02/15/apple-ce...