Income can come from thousands of sources. TurboTax does not know the source of your income unless you tell it. If you went through the entire interview without bypassing sections then it would ask about SS income in the retirement section. The bottom line is that you are responsible for double checking your return before filing to be sure that you reported all of your income.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**