FAIR VALUE MEASUREMENTS Table 2 (Details) (NS unit options [Member])	9 Months Ended	12 Months Ended
	Sep. 30, 2011	Dec. 31, 2010
NS unit options [Member]
The fair value of our accrued compensation expense for NuStar Energy unit options is determined using the Black-Scholes option-pricing model on the reporting date based on the following weighted-average assumptions:
Expected life in years	6.3	6.3
Expected volatility	20.90%	23.30%
Expected distribution yield	8.40%	6.20%
Risk-free interest rate	0.10%	0.40%