Can I get itemized, per-resource billing detail through a CSP partner invoice?

Yes — while your invoice from the partner is typically consolidated at a summary level, the underlying detailed usage data (down to individual Azure resources) is still available, usually through Azure Cost Management tools within your own tenant, or via detailed reports your partner can provide on request.

If granular, resource-level cost visibility is important to you, it's worth confirming with a partner upfront what reporting they provide by default versus what needs to be requested.