I happen to have an IRA with them, and I have been using it as the income anchor for my portfolio since it gives access to the "TIAA Traditional Annuity". From the prospectus:
"A guaranteed annuity backed by TIAA’s claims-paying ability, TIAA Traditional guarantees your principal and a 3% minimum annual interest rate."
I am planning to use this TIAA Traditional as the cash portion of my PP. It just so happens it's about 25% of my overall portfolio, and it also happens that, as an early retiree, this is the account I will start drawing living expenses from beginning in a couple of years. So it is comforting that it does nothing but grow!

The only concern I can see with this plan is, what if TIAA goes bust? It seems a low probability event, what with the highest possible ratings from A.M. Best, Moody's, Fitch and S&P.
Drewskers