This video from Grakn Labs, Building a Digital Tax Accountant with a Knowledge Graph Mind, walks you through how to build a tax expert system (in this case Taxfix).
These same ideas can be used to create an accounting and financial reporting oriented expert system for US GAAP and/or IFRS or any other financial reporting scheme.
You might find it useful to check out these three articles:
Clearly a tax reporting system, an accounting related expert system, a financial reporting related expert system, an audit related expert system, or an analysis related expert system would work differently and have different work flows; but fundamentally, these are all the same sorts of things.
Here is how a software engineer and I built a working prototype expert system for creating XBRL-based financial reports and verifying that the reports were properly functioning. This video play list shows what we created. You can download it and try it out (email me and I will send you a license good for a year).