Can Cost Explorer show the actual resources/services behind activated cost-allocation tag values?

Cost Explorer itself doesn't provide a direct way to list the specific resources (like individual EC2 instances or S3 buckets) that contribute to costs for a particular tag value. While Cost Explorer allows you to group and filter costs by tags, it operates at a higher level of aggregation.

To map cost allocation tag values to specific resources, you have a few options:

1. Use the AWS Cost and Usage Report (CUR) - This is the recommended approach for detailed analysis. The CUR provides comprehensive cost and usage data, including resource IDs and their associated tags. Each activated cost allocation tag appears as a separate column in the report, making it easier to identify which specific resources have which tags.

2. Filter in Cost Explorer by both tag and service - While you can't see individual resources, you can at least narrow down which AWS services (EC2, S3, RDS, etc.) are contributing to costs for a specific tag value by applying both tag and service filters simultaneously.

3. Use the monthly cost allocation report - This report lists AWS usage by product category and includes tag keys, though it's less detailed than the CUR and AWS recommends using the CUR instead.

For the minimal permissions required to perform this mapping:

• To access Cost Explorer: ce:* permissions
• To access and create Cost and Usage Reports: cur:* permissions
• To view billing information: aws-portal:ViewBilling or the newer billing:ViewBilling
• To view resources across services (for verification): Read-only permissions for the relevant services

Note that deleting or deactivating resources with certain tags doesn't always reduce costs immediately, so it's important to understand the full context when analyzing tagged resources.
Sources
Organizing and tracking costs using AWS cost allocation tags - AWS Billing
Building a cost allocation strategy - Best Practices for Tagging AWS Resources
Cloud Financial Management – AWS Cost Explorer - Amazon Web Services
Using the monthly cost allocation report - AWS Billing

Hi, On the service part, this should be a case of setting the Cost Explorer filter to the relevant cost allocation tag then use groupby service dimension

For the resource aspect - It may be worth looking at resource level granularity in Cost Explorer. Once enabled it (takes ~ 48hrs) it will provide resource level granularity for some services for the last 14 days.

https://docs.aws.amazon.com/cost-management/latest/userguide/ce-resource-daily.html

Once enabled, you could try using the setting the cost explorer filters to the cost allocation tag then groupby resourceid.

The Cost & Usage Report (CUR) has the most comprehensive set of billing data and may be another avenue, but may require some queries. https://docs.aws.amazon.com/cur/latest/userguide/what-is-cur.html