Some new pledges are expected here but EU officials acknowledge it may take a long time for the target to be met amid misgivings about how effectively the money will be used.
The leaders are due to approve a plan of action and a common statement on the issues on Thursday, when the summit wraps up after lunch.
European Union leaders will then hold a meeting of their own which will focus on fostering better cooperation with Turkey to try and reduce the numbers of refugees using the country as a launchpad for trips to Europe via Greece and the Balkans, now the main migrant route.