INVESTMENT IN NUSTAR ENERGY Narrative 3 (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2001
Description of step-up in basis related to NuStar Energy's assets and liabilities [Abstract]
Unamortized step-up in basis related to NuStar Energy's assets and liabilities	$ 81.8
Step-up in basis related to NuStar Energy's assets and liabilities, amortization period, in years	28
NuStar Energy [Member]
Description of step-up in basis related to NuStar Energy's assets and liabilities [Abstract]
Valero Energy's proportionate interest in NuStar Energy's identifiable assets and liabilies	73.60%
Percent of equity interest in NuStar Energy owned by public unitholders	26.40%