INVESTMENT IN NUSTAR ENERGY Narrative 3 (Details) - NuStar Energy Series B Preferred Unit Issuance [Member] - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Jun. 30, 2017	Apr. 28, 2017
Schedule of Equity Method Investments [Line Items]
Limited partner units issued by NuStar Energy	15,400,000
Price of preferred units issued by NuStar Energy, per unit		$ 25.00
Net proceeds received by NuStar Energy from issuance of units	$ 371.8
NuStar Energy's preferred units distribution rate	7.625%
Liquidation preference of NuStar Energy's preferred units	$ 25.00
Minimum per unit quarterly distribution of NuStar Energy's preferred units, annualized	$ 1.90625
Description of floating dividend rate of NuStar Energy's preferred units	three-month LIBOR plus a spread of 5.643%