Broad built a fortune of more than $7 billion from two companies, Kaufman & Broad, the first homebuilder to trade on the New York Stock Exchange, and SunAmerica, one of the largest U.S. annuity providers.
Canadian actors Ryan Reynolds, Michael J. Fox and basketball player Kelly Olynyk also participated in the funding round.
Warren Buffett said the 58-year-old executive will take over the $630 billion business when he steps down.
The supermarket chain is partnering with Drone Express to deliver groceries.