It's not an Amex specific thing. Most major cards support this. Although many don't indicate it on the statement like Amex. It's called a 1644 Financial Detail Message, and it's available to certain merchants that use top tier payment gateways. (i.e. it's not something you'll find with your Quickbooks Merchant Account).

It can include passenger transport data (plane, train, boat), Rental Car Detail, Lodging Detail, Shipping/Courier, Telephone Services, Electronic Invoices, and Fleet Transactions. There is a surprising amount of information that can be transmitted to a credit card company.

The most common uses are Transport, Lodging and Rental Car data. It can be to trigger various loyalty and insurance programs associated with a card.