Is the Billing input required in addition to the Cost and Usage Input to see the billing details for AWS accounts? If I just setup the Cost and Usage input, I can see the sourcetype for aws:billing:cur for the 2 accounts I have discovered in the App for AWS UI, however when executing the default reports in the Search and Reporting UI, I am only getting the details of one of the accounts. That account that I get the details for just happens to be the same account that I went ahead and setup both CUR and Legacy Billing inputs on.
All documentation points to dashboards and reports that rely on the aws:billing sourcetype so I'm trying to figure out if I need both configured or what I should expect to see with just the Cost and Usage input configured.
However, the Billing reports and dashboards in the AWS App still only make use of data from the Billing (Legacy) inputs at this time, so you will want to configure those as well to populate that data for now.