The Survey also reports household net worth by age group, which combines cash and investments, retirement accounts, real and personal property, and debt.
Median net worth in households where the head is between 65 and 74 years old is about $410,000. This is the richest age group. Their personal real estate equity is more than $250,000, so their total invested assets is not great. 35-44s NW is ~$135k; 45-54s, ~$250.
And the median is positively skewed. I believe almost 40% of Americans nearing retirement age have practically nothing saved and will rely mostly on SS.