With a volume of transactions that large, you are likely going to want to use the summary method of reporting as there is a 500 transaction limit in the online version of TurboTax. The summary method allows you to enter the summary totals from your brokerage statement in lieu of the individual details. The following TurboTax FAQ has a detailed breakdown of how to follow this reporting method (its fairly simple, but you will need to print a few forms and mail them separately to the IRS).
https://ttlc.intuit.com/replies/4926553
