As has been already said, chances are policy varies around the globe.
When asking your insurance company, do take care to be very precise when asking if you are already covered.
When I initially asked my insurer, they replied that 'Sure, cameras are covered by your homeowner's policy' - until I specified that 'cameras' did not equate a couple of point-and-shoots, but rather a few Nikon bodies, a Leica, a Pentax 67 and assorted glass to go along with them.
I was then asked to prepare a list with serial numbers and estimated value, preferably with a photo of the gear attached. My premium did not increase significantly - basically, they just wanted me to substantiate the fact that I did actually own all this (second-hand, and most of it with no receipts) kit.
My kit would have been covered even without such a list - it was just a recommendation to ease the process should I ever have to collect on my insurance.
Also, it is prudent to ask them to explicitly name any events not covered by your policy; for instance, my homeowner's insurance covered all cameras on all travels lasting less than 28 days; if I were gone any longer, coverage was transferred to my travel policy.
If I went traveling on business, my homeowner's didn't come into play at all - then it was travel insurance from day one, even if I only went shooting on my time off. (Travel insurances typically have a cap on how much they will pay out in the event of theft or loss - hence it is an important distinction.)