In 2015 - I contributed more than $18K in 401k. Today, I received a "return" of my excess contribution. How do i report this on my 2015 taxes ?

I am getting conflicting answers.   The plan administrator told me they will send me a 1099-R in 2017 (for 2016 tax year),  but I should report the "excess" in 2015 taxes, while any income on the excess in 2016 taxes....s income in 2015 and report ny