Prior to July 2017, charges for CloudWatch were split under two different sections in your AWS bill and Cost and Usage Reports. For historical reasons, charges for CloudWatch Alarms, CloudWatch Metrics, and CloudWatch API usage were reported under the “Elastic Compute Cloud” (EC2) detail section of your bill, while charges for CloudWatch Logs and CloudWatch Dashboards are reported under the “CloudWatch” detail section. To help consolidate and simplify your monthly AWS CloudWatch usage and billing, we moved the charges for your CloudWatch Metrics, Alarms, and API usage from the “EC2” section of your bill to the “CloudWatch” section, effectively bringing together all of your CloudWatch monitoring charges under the “CloudWatch” section. Note that this has no impact to your total AWS bill amount. Your bill and Cost and Usage Reports will now simply display charges for CloudWatch under a single section.
Additionally, there is a Billing Metric in CloudWatch named “Estimated Charges” that can be viewed as Total Estimated Charge or broken down By Service. The “Total Estimated Charge” metric will not change. However, the “EstimatedCharges” metric broken down by Service will change for dimension ServiceName equal to “AmazonEC2” and dimension ServiceName equal to “AmazonCloudWatch”. Due to the billing consolidation, you may see that your AmazonEC2 billing metric decrease and AmazonCloudWatch billing metric increase as usage and billing charges get moved out of EC2 and into CloudWatch.