Online Call Details are a list of all the incoming and outgoing calls associated with your account. They are available to view anytime when you login to your account. Call detail records, or CDRs for short, can be searched by any date range using the calendar tool. They show the date, the caller ID, whether it was on incoming or outgoing call, the length of the call and the cost. There is also a summary at the bottom of the report that shows the total number of calls, the total duration and the total cost.
Call detail records are useful if you want to track your calls or you want to charge a call to a 3rd party. Your CDRs will give you all the information you need.