Amazon, the retail and tech giant with 275,000 full-time U.S. employees, will retrain a third of its domestic workforce to get ahead of technological changes that could overhaul warehouses, retail stores, transportation networks and corporate offices alike.

The company on Thursday announced the $700 million initiative that will cover 100,000 workers by 2025. The program will build on existing training programs and add workshops that can help employees move up within the company. The training is not mandatory but marks a corporate emphasis on building skills for current workers, even if that means teaching them tools that apply beyond their current day-to-day roles.

“While many of our employees want to build their careers here, for others it might be a steppingstone to different aspirations,” said Beth Galetti, Amazon’s senior vice president for HR. “We think it’s important to invest in our employees, and to help them gain new skills and create more professional options for themselves.”

Amazon’s retraining programs falls in line with a broader push among U.S. companies to help workers advance. For Amazon, that often means anticipating how technology will continue to revamp warehouses and other centers worldwide, and figuring out how those advancements will shape tens of thousands of individual jobs. The company expects to reach an employment level of 300,000 people in the United States this year and has more than 630,000 workers worldwide.

The announcement also comes at a time of historically low unemployment that has left companies large and small struggling to fill their ranks. Amazon in particular has thousands of current job openings, and its retraining initiative suggests the company only expects its roles to become more technical. The investment isn’t only about equipping current workers with the tools to adapt to changing jobs, experts say, but is also about holding onto employees who may look for other options elsewhere.

The Wall Street Journal first reported the news of the retraining initiative. Amazon chief executive Jeff Bezos owns The Washington Post.

Amazon has already been tinkering with how to upgrade existing jobs. For example, it has rolled out the gamification of warehouse gigs. Inside several warehouses, hundreds of employees complete their jobs while playing video games, some with virtual dragons or sports cars racing around a track. And while the games are primarily meant to tackle the tedium of warehouse jobs, it’s a welcome bonus for the company if the interactive games also increase the efficiency of picking items out of boxes or stowing them back on shelves.

Still, Amazon has routinely come under fire from workers’ groups and politicians, including Sen. Bernie Sanders (I-Vt.), a Democratic presidential contender. Sanders and others support employees trying to form a union and have called for better conditions within cavernous warehouses, particularly after employee complaints of workplace injuries and extreme temperatures.

But Amazon points to its decision to raise the minimum wage for U.S. employees to $15 per hour, and has denied allegations of unsafe working conditions. Bezos has also called on other retail competitors to match Amazon’s minimum wage. (The company’s pay bump also coincided with cuts to employee bonuses and stock grants.)

The new training will include programs for nontechnical employees to transition into software engineering careers. The training also covers courses for Amazon Web Services and cloud skills. And Amazon is also growing its Career Choice program for warehouse employees, which pays almost all of tuition and fees toward degrees or certifications in fields from transportation to health care to IT; Amazon expects to have over 60 on-site classrooms by the end of next year.

For a company as multifaceted as Amazon, one challenge will be accurately anticipating the range of changes affecting workers five or 10 years down the line, said Patrick Penfield, a professor of supply chain management and director of executive education at Syracuse University’s Whitman School of Management. Technology morphs and advances faster than many companies can keep up, and can look different across Amazon’s shipping, retail, cloud and logistics empire.

It’s a test Amazon knows all too well. Penfield said that a decade ago, some may have scratched their heads at the thought of robots picking items off shelves in place of human workers.

“Technology is changing, and it’s going to change again,” Penfield said.

“If you have a business and you’re not changing with the times, you won’t be in business long,” Penfield said.