I think about $150 million.
considering CPI index original about 10 million
in 2009 dollars $ 289,546,168.25
Asheville, NC.
George Vanderbuilt only inherited around $12 million from his Father and Grandfather, plus drew some money from a $5 million trust fund.
The Biltmore House is estimated to have cost around $10 million to complete but the exact figure isn't known. However, it was nowhere close to $150 million dollars.