Access Query Count multiple types and Update table

I hope the title is correct. I want to identify ClientId that have multiple DocType.

ClientID            DocType
00004            1

00011            1
00011            1
00011            1
00011            2
00011            2

00015            1
00015            3

00020            1
00020            1
00020            1

In the above example ClientID 00011 and 00015 have multiple types. CliendID 00004 and 00020 do not. I want to then Update a field on the table tbl_Clients.MultiType with a "*" for clients that have the multiple types