In terms of the $1 million fee, that's has been plucked out of the air. The newspapers have slowly been increasing their apparent fee.
It can be very lucrative though:
Al Gore - $100,000
Condoleeza Rice - $150,000
George W. Bush - $150,000 and $200,000
Tony Blair - $200,000
Alan Greenspan and Arnold Schwarzenegger - $250,000 each
Bill Clinton - $260,000
Ben Bernanke - $200,000 and $400,000
Barack Obama - $400-600K
Donald Trump - $1.5 million*
*Donald earned a staggering $1.5 million per speech at The Learning Annex’s ‘real estate wealth expos’ in 2006 and 2007,” according to Forbes. “Trump appeared at 17 seminars and collected this fee for each one.”
Attached - BBC stars 2018 appearance fees (speeches, hosting of small awards shows, etc)