Starting today, we are extending the history and improving the granularity of data available in AWS Cost Explorer. AWS Cost Explorer by default now supports 14 months of cost and usage data at daily granularity, up from 13 months. In addition, customers have the option to enable up to 38 months of history at a monthly granularity, and they have the option to enable 14 days of resource level data for any AWS service at daily granularity. Each of these features is offered for free.
Source:: Amazon AWS