In what is one of the biggest corporate retraining initiatives ever announced, Amazon said Thursday morning that it will invest $7,000 per worker to retrain 100,000 employees (a third of its workforce) by 2025 to allow them to do higher tech jobs or to enter more technical careers.

And those jobs don't even have to be at Amazon.

Of course, Amazon hopes that the investment keeps its employees close to home. The retraining programs will help workers move into a variety of jobs across Amazon's tech hubs, fulfillment centers, corporate HQ, retail stores, and transportation network.  

According to CNBC, Amazon has identified its fastest-growing skilled/technical job positions over the past five years as data mapping, data science, security engineering, business analysis, and logistics and transportation.

Some of the specific programs will include the Amazon Technical Academy, which trains people to be software engineers, Machine Learning University, which enables upgraded skillsets in machine learning for current tech employees, and Amazon Career Choice, a pre-paid tuition program designed to move fulfillment center workers into careers of their choosing (again, even if these careers take them outside of Amazon, like nursing or airplane mechanics). The company will have 15 new Career Choice centers opening by 2020, as new fulfillment centers open.

All of the training is voluntary and free to employees.

Here's why Amazon's massive investment is such a brilliant move.

Sure, it's a massive expense, but as Chris O'Leary, a senior economist at the W.E. Upjohn Institute for Employment Research, a nonprofit research center, indicates, the cost of recruiting new workers and training them is massive too. Not to mention the hit to morale as Amazon workers would watch a constant stream of friends and co-workers rolling out the door to greener pastures.

Amazon has been struggling like everyone else to hire and retain enough tech-skilled workers, and has now started to solve the problem right at home, with the current workforce.

Such massive announcements make Amazon employees feel invested in. Said one Amazon employee I interviewed for this article, "The fact that this company is willing to do something, not just say something, about me having a better life, well, that's a big deal to me." 

But what about the fact that the company is spending $700 million on 100,000 employees and, in theory, every single one of them is free to leave right after his or her training is complete? Isn't that poor business?

Absolutely not. I'd venture to say that in 2025, when the retraining initiative is complete, the percent of employees who will have actually left Amazon, despite all the opportunities and avenues that will have been opened to them, will be far lower than it would have been had the company continued on without the initiative.

It's a brilliant way for Amazon to put its money, and its heart, where its mouth is.