FAIR VALUE MEASUREMENTS Table 2 (Details) (NS unit options [Member])	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2011
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	6.5	6.5
Expected volatility	23.40%	22.40%
Expected distribution yield	8.20%	10.30%
Risk-free interest rate	0.20%	0.20%