Microsoft today announced that it's cutting 18,000 jobs, the biggest round of layoffs in its history, as part of ongoing restructuring efforts. In a release, the company says that Nokia's Devices and Services business, which it acquired for $5 billion last year, will be most affected, with 12,500 "professional and factory positions" expected to go by the end of the year. In an email to employees, Microsoft CEO Satya Nadella explains that the company's new strategy is designed to make it "more agile" moving forward, allowing teams to work more freely.Nadella also hinted that Microsoft could end development of Nokia's Android-powered X smartphones by shifting "select Nokia X product designs to become Lumia products running Windows." As for the Xbox and Surface divisions, they'll see "limited change," as the company intends to continue building on plans it implemented earlier in the year. Nadella believes today's cuts will go some way towards helping Microsoft realign itself, allowing it to pursue its goal of innovating both in mobile and the cloud.