DEBT AND OTHER OBLIGATIONS - Letters of Credit (Details)	9 Months Ended
	Sep. 30, 2016 USD ($) installment	Jun. 25, 2014 USD ($)	Aug. 07, 2013 USD ($)	Dec. 10, 2010 USD ($)	Apr. 23, 2010 USD ($)
Golden Gate III
Debt Instrument [Line Items]
Maximum LOC borrowing capacity		$ 915,000,000	$ 710,000,000		$ 505,000,000
Maximum stated amount up to which LOC may be increased		$ 935,000,000	$ 720,000,000		$ 610,000,000
Letter of credit term	15 years
Future scheduled capital contributions to prefund credit enhancements fees amount	$ 122,500,000
Number of installments for payment of capital contributions amount | installment	3
Golden Gate IV
Debt Instrument [Line Items]
Maximum LOC borrowing capacity				$ 270,000,000
Letter of credit term	12 years
Successor | Golden Gate III
Debt Instrument [Line Items]
Outstanding letters of credit (LOC)	$ 935,000,000
Successor | Golden Gate IV
Debt Instrument [Line Items]
Maximum LOC borrowing capacity	790,000,000
Payments made under the agreements	$ 0