Yeah, they were always talking about "total devices", meaning Windows phones/tablets, Surfaces, laptops, in addition to their traditional mainstay of home and business desktops.
It _IS_ a lot of machines. No question about it. But the trend is not great. Look how many Windows 7 machines they have to still convert, to swap places:
Those curves are nearly flat -- Win7 at just below 50%, Win10 at about 25%. They still have to convert at least half of the remaining Windows 7 machines to Windows 10. At the rate of the past half year, it'll take until long after Win7 is dropped from support (Jan 2020) to make that happen.
The above curves were snapshotted from NetMarketShare's site a few minutes ago.