Cannot increase size for docker container - Ubuntu 16.04

I tried running

docker run --memory=16g -ti -v [...]

But on my other terminal when I run docker stats, it always show that

MEM USAGE / LIMIT 48.89 MiB / 3.724 GiB

And it seems like 3.724Gb is the upper bound of the limit - if I rerun with only --memory=1G then it will accept.

Can I increase/change this?