The default deployment descriptor files are:
In cases where you want to provide your own descriptor files or if the descriptor files are located somewhere else, you can use the following on the command-line:
mvn idea:idea -DdeploymentDescriptorFile=src/webapp/WEB-INF/web.xml
For a multiproject setup, where you'll want to have different values for this parameter for projects that use it, you should put the configuration values in their respective poms like so:
<project>
[...]
<build>
[...]
<plugins>
[...]
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-idea-plugin</artifactId>
<version>2.2.1</version>
<configuration>
<deploymentDescriptorFile>src/webapp/WEB-INF/web.xml</deploymentDescriptorFile>
</configuration>
</plugin>
[...]
</plugins>
[...]
</build>
[...]
</project>