Depends on the position that you interviewed for.
It took about a month.
Answered - Metering Services Intern (Former Employee) - Garner, NC
At least 1 week
Answered - Financial Customer Service Representative (Former Employee) - Greensboro, NC
It can take 1-2 weeks after an interview to hear back from the company. Be politely persistent.
Answered - Manager (Current Employee) - Charlotte, NC
You may never get a response. Duke is notoriously bad about interview follow up.
Answered - Strategy Manager (Current Employee) - Charlotte, NC