This is a difficult question to answer because Amazon does not release this information publicly. However, we can make some educated guesses based on what we do know about Amazon's compensation structure.
Based on Amazon's most recent compensation report, the median salary for all employees is $28,446. However, this number is likely skewed low because it includes all employees, including part-time and temporary workers. Senior management and executives probably make significantly more than this.
In 2018, Jeff Bezos made $1.68 million in salary and bonuses. He also received $1 billion in stock awards and $800 million in option awards. So, his total compensation for the year was around $3.5 billion.
Keep in mind that Bezos owns a significant amount of Amazon stock (he owns about 16% of the company), so his compensation is largely dependent on how well the stock does. For example, in 2017 his compensation was $1.68 million in salary and bonuses, but $5.3 billion in stock awards and options because Amazon's stock had a great year.
So, while we can't say for sure what Jeff Bezos' exact salary is, we know that it is probably quite high and that his total compensation varies depending on how well Amazon's stock does.