Yes, but not at the same time.
You can download it on as many PCs/Macs as u want, only 2 CC liscenses can be active at a time, and only 1 copy of each program can be open at a time.
I have a copy on my Home PC, my Work PC, and the Surface Pro. Its as simple as signing out the other 2 from whichever one im on to be able to use it on the 3rd.
You can have it "Active"/usuable on 2 computers at a time, but can download to multiple computers.
Example Scenario in my actual life, you have a Windows Laptop and an iMac that you have Photoshop CC on (which was more difficult prior to Creative Cloud by the way), but you know you are going to visit your girlfriend out of state for a week.
You can deactivate Photoshop on your iMac while you're away without out uninstalling it.
Once you'e at her place you can download and activate Photoshop CC and you can even import you custom settings, Work Area and shortcuts all from the cloud. Now you can work seemlessly
Another example, you're office won't pop for the latest version of Photoshop and still has you running CS5.5
You have your own copy of Photoshop CC but don't want to just "give" them your license or key since their too cheap to get one for you for your work, but you still need those features to be at your best.
You can deactivate your license on your desktop or laptop in the morning when you are heading to the office, activate on your work computer, and deactivate before you clock out and go home.
As J pointed out, you can have it active on 2 machines at once, but installed on any machine you plan to work on at some point. Take advantage of it!