This article:
http://www.dailyreckoning.com/rpt/OilShale.html
says the total oil in shale for the entire U. S. is at least 1.5 trillion barrels.
The total oil in place for oil shale in the US is estimated to be over 2 trillion.
The estimated recoverable oil from the Green River formation is 800 billion barrels.
The reporter made a typo with billion versus million.
Links for the above already posted in the thread.
Cheers