A company runs 90 AWS accounts in one organization in AWS Organizations with all features enabled. Finance wants monthly chargeback by cost centre, but the first attempt failed: teams tag resources with CostCenter, costcenter, and cost-center, and some use values that are not real cost centre codes. Even resources that are tagged correctly never show up as a grouping dimension in AWS Cost Explorer.
The platform team must standardize one tag key with a fixed case and a fixed list of allowed values across every account, block tagging requests that use a noncompliant value on the resource types that matter most, see compliance for the whole organization from one place, and make the tag usable in Cost Explorer and the cost allocation report. Which approach meets all of these requirements?