Currently, enabling Cloud Billing export to BigQuery can only be done through the GCP Console UI — there is no gcloud CLI command or stable REST API endpoint to configure it. The /v1/billingAccounts/{id}/exportSettings endpoint returns 404, and there is no Terraform resource for it either.
This is a significant gap for anyone trying to fully automate GCP project setup via CLI or IaC, since billing export is the only major billing configuration that requires manual Console interaction.
I’ve filed a feature request here: https://issuetracker.google.com/issues/504194143
If you’ve hit this same limitation, please star the issue to help prioritize it. Would love to hear if anyone has found a workaround.