This playlist explains how to cite books, articles and websites using Chicago Author-Date style. There is an additional video explaining how create in-text citations and reference lists.
You can cite a FASB Code in the same way that you cite a website. The following is an example:
Financial Accounting Standards Board (FASB). “ASC 905-325-35-2,” Accounting Standards Codification, accessed
September 21, 2015, https://asc.fasb.org/.
Use n.d. in your in-text citation if no publication date exists. For example: (Financial Accounting Standards Board n.d.)