VARIABLE INTEREST ENTITIES - Consolidated VIEs (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
ASSETS (LIABILITIES)
Accounts receivable and other	$ 34	$ 37
Inventories	7	7
Other current assets	4	5
Equity investments	1,062	1,044
Plant, property and equipment	1,866	1,881
Other assets	1	1
Accounts payable and accrued liabilities	(24)	(27)
Accounts payable to affiliates	(6)	(7)
Accrued interest	(13)	(9)
Current portion of long-term debt	(23)	(23)
Long-term debt	(1,786)	(1,835)
Other liabilities	(28)	(28)
Consolidated VIEs | Restricted VIEs
ASSETS (LIABILITIES)
Accounts receivable and other	21	24
Inventories	6	6
Other current assets	3	4
Equity investments	1,062	1,044
Plant, property and equipment	844	847
Other assets	2	2
Accounts payable and accrued liabilities	(18)	(20)
Accounts payable to affiliates	(21)	(28)
Accrued interest	(5)	(1)
Current portion of long-term debt	(23)	(23)
Long-term debt	(313)	(313)
Other liabilities	$ (26)	$ (25)