VARIABLE INTEREST ENTITIES - Consolidated VIEs (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
ASSETS (LIABILITIES)
Accounts receivable and other	$ 37	$ 33
Inventories	7	7
Other current assets	5	2
Equity investments	1,044	965
Plant, property and equipment	1,881	1,949
Other assets	1	1
Accounts payable and accrued liabilities	(27)	(32)
Accounts payable to affiliates	(7)	(5)
Accrued interest	(9)	(8)
Current portion of long-term debt	(23)	(14)
Long-term debt	(1,835)	(1,889)
Other liabilities	(28)	(27)
Consolidated VIEs | Restricted VIEs
ASSETS (LIABILITIES)
Accounts receivable and other	24	21
Inventories	6	6
Other current assets	4	4
Equity investments	1,044	965
Plant, property and equipment	847	872
Other assets	2	2
Accounts payable and accrued liabilities	(20)	(26)
Accounts payable to affiliates	(28)	(6)
Accrued interest	(1)	(1)
Current portion of long-term debt	(23)	(14)
Long-term debt	(313)	(326)
Other liabilities	$ (25)	$ (24)