Yes, there is a way to partially measure that in AdWords, it is called “Attribution” (formerly called “Search Funnels”), and to properly measure it requires a technique called attribution modeling.
One thing to keep in mind is that the results of Branding campaigns need to measure across a range of marketing channels, this type of measuring is usually referred to as “Multi-channel attribution”. If you are using Google analytics you will find multi-channel reports that will help you gain even more attribution data on your Branding campaigns.
