A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
That feature has been removed (at least in 2013. No knowledge of previous versions). Gone are the days of a good help documentation. Worst is VBA help. Now, there is no offline VBA help. Help in VBA takes you to MS VBA site for the help.
But if you are using Formulas > Insert Function, then you get access to that function's help.