DEBT - 2016 Credit Agreement (Details) $ in Millions	1 Months Ended	9 Months Ended
	Aug. 31, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)	Oct. 31, 2014 USD ($)
Debt
Repayment of revolving credit facility		$ 1,010	$ 1,728
2016 Credit Agreement (Secured First Lien)
Debt
Original issue discount	$ 10
Aggregate principal amount issued	$ 1,000	1,000		$ 1,000
2016 Credit Agreement (Secured First Lien) | Applicable margin on Alternate Base Rate loans
Debt
Interest rate added to variable rate basis (as a percent)	10.375%
Floor rate (as a percent)	1.00%
2016 Credit Agreement (Secured First Lien) | Applicable margin on LIBOR loans
Debt
Interest rate added to variable rate basis (as a percent)	9.375%
2016 Credit Agreement (Secured First Lien) | Any June 30 and December 31
Debt
Minimum asset coverage ratio	1.20
2016 Credit Agreement (Secured First Lien) | 5% Notes Due 2020
Debt
Outstanding amount that triggers accelerated payment		$ 100
Period before maturity of the specified notes		91 days
2016 Credit Agreement (Secured First Lien) | 5.5% Notes Due 2021
Debt
Outstanding amount that triggers accelerated payment		$ 100
Period before maturity of the specified notes		91 days
Senior Notes (Unsecured)
Debt
Aggregate principal amount issued					$ 5,000
Senior Notes (Unsecured) | 5% Notes Due 2020
Debt
Aggregate principal amount issued					1,000
Senior Notes (Unsecured) | 5.5% Notes Due 2021
Debt
Aggregate principal amount issued					$ 1,750
Term Loan Facility | 2014 Credit Facilities (Secured First Lien)
Debt
Proceeds used to repay 2014 revolving credit facility	$ 250
Revolving Credit Facility | 2014 Credit Facilities (Secured First Lien)
Debt
Repayment of revolving credit facility	$ 740