Wow... Billionaire... I've never played that high before. But....
Keep working (honestly) until I was replaced and the replacement was properly trained. I'd also find new offices for the association I work for and set them up with a paid 20 year lease. I'd also set up a protected fund that would generate income to augment their salaries and benefits.
I've had a couple of ideas for businesses that I want more to be a part of than be the one who runs it so I'd partner with someone (or pay them handsomely since I'm a billionaire now) and have them help me set them up. I couldn't ever not work at something at all. I'd be too bored. So I want something that I can come in and out of at my leisure.
1. Saying "I know, right?!?"