The iPhone 6 costs $240 to make in China: https://technology.ihs.com/528618/samsung-galaxy-s6-edge-pricier-to-build-cheaper-to-buy-than-comparable-apple-iphone-6-plus According to the World Bank, China produces about 0.7 kg of CO2 per dollar of GDP (probably lowballed due to the PPP adjustment). Therefore each iPhone results in 168 kg of CO2 or .168 metric tons. Apple sold about 170 million iPhones in 2014 which equates to 28.5 million metric tons, just for the manufacturing of iPhones.
What? Apple's China assembling contractor FoxConn's revenue is nowhere near what you are claiming. That would make Apple's contribution to FoxConn's bottom line ~$40 billion. . . in China, when FoxConn, the manufacturer of Apple's iPhone and manufacturer of the goods for over 500 other makers' electronic goods, was only $31.18 Billion. The problem in your calculation is that much of the components in Apple's iPhone and iPads come from all over the world, not just China. Those components are merely assembled in China. I think there are products from over 60 nations involved in the construction of one iPhone.
Apple is including all the transportation, including employees cars going to work, plane flights, shipping of parts and finished products, generating electricity, coal for heating the metals for smelting, mining, etc., and you name it, every step in the downline of their product chain, in the figures Apple use for "their" carbon footprint and not all of it is in China.