If I had a 401k that I directly rolled over into my new employer's 401K, how does this need to be reported? I did not receive a 1099R

[Carl]

If *you* never touched the money, no 1099-R is issued and you have absolutely nothing to report concerning the rollover. It's referred to as a trustee-to-trustee transfer, and no reporting is necessary or required.

[dmertz]

Carl comment is referring to a transfer of one IRA to another, not to the movement of a 401(k).  If either the old employer's plan or the new employer's plan was really a 401(k), a Form 1099-R is *required* to be issued by the old employer's plan and is required to be reported on your tax return.  Are you sure that these were 401(k) plans?

If either plan is a 401(k) plan, contact the old plan administrator to obtain the missing Form 1099-R.

[DawnC0]

As long as you did a 'direct rollover' or a 'trustee to trustee' transfer and never had the money, there are no tax implications to you for 2017.   You may wish to confirm this was how the transfer was done.  You would have completed paperwork and both your former and new employers' plans will have this information.