Although permissions on projects, as well as primitive roles Project Owner, Editor or Viewer, allow to view reports for those projects, to see the billing reports and configured labels for all Cloud projects that are linked to the billing account require the billing.accounts.getSpendingInformation
permission on the linked Cloud Billing Account. This permission is part of the IAM billing roles
- Billing Account Administrator
- Billing Account Viewer
See Cloud IAM > Doc > Understanding roles > Predefined roles > Billing roles
To query usage by project label, the project.labels
field in the Billing Export data can be used.