User: Who is the greatest quarterback of all time?
Assistant: Tom Brady is widely considered to be the greatest NFL quarterback of all time. He holds the all-time records for Passing Yards, Passing Touchdowns, Completions. 

Brady also has a record 7 Super Bowl championships, 3 more than any other quarterback and a record unlikely to be broken. He won 6 of these with the New England Patriots, with whom he spent the first 20 years of career. 

After early-career comparisons to his contemporary rival Peyton Manning, and mid-career comparisons to another all-time great Joe Montana, Brady ended his career as the indisputable Greatest of All Time (GOAT) by playing at an extremely high level for multiple decades.