AWS Billing and Cost Management now provides billing context for your account through a new API

AWS Billing and Cost Management now offers the ListBillingViewSegments API, which returns the billing context of your account over a time period you specify. You can use the API to retrieve information about how your accounts are positioned in the billing hierarchy, such as management accounts, member accounts, or billing group primary accounts. You can also identify which accounts managed your billing relationship and the rate settings, either billable or pro forma, applied to your cost data.