DEBT - Credit Facilities (Details) shares in Thousands, $ in Millions	1 Months Ended						2 Months Ended	3 Months Ended	12 Months Ended
	Jan. 31, 2017 USD ($)	Oct. 31, 2016 USD ($) shares	Aug. 31, 2016 USD ($)	May 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($)	Oct. 31, 2014 USD ($)	Feb. 29, 2016 USD ($)	Dec. 31, 2016 USD ($) item	Dec. 31, 2016 USD ($) item shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($)	Nov. 01, 2016 USD ($)	Sep. 30, 2016
Debt
Outstanding borrowings					$ 6,143			$ 5,268	$ 5,268	$ 6,143
Repayment of term loan									350
Repayment of revolving credit facility									2,110	1,656	$ 155
Pre-tax gain on repurchase of debt									805	20
Financial performance covenants
Debt issuance costs									$ 51	$ 11	$ 70
Number of shares issued | shares									3,725	254
2014 First Out Credit Facilities (Secured First Lien)
Debt
Maximum principal amount of unsecured senior notes that may repurchase									$ 140
Percent of commitment required to decrease or affirm the borrowing base								67.00%	67.00%
Number of consecutive redeterminations | item								3	3
Financial performance covenants
Minimum monthly liquidity								$ 250	$ 250
Liquidity	$ 486
Percent of proceeds from asset monetization which must be used to repay loans outstanding under the 2014 First Out Credit Facilities									100.00%
Maximum percent of proceeds from non-borrowing base asset sales that may be used to repurchase notes									50.00%
Percentage of proceeds from non-borrowing base asset sales used to repurchase debt if leverage ratio is less than 4:00 to 1:00									60.00%
Maximum additional non-Credit Facility indebtedness									$ 50
Amount of cash on hand above which amounts owed under the Revolving Credit Facility must be repaid									$ 150
2014 First Out Credit Facilities (Secured First Lien) | One-Month LIBOR
Debt
Interest rate added to variable rate basis (as a percent)									1.00%
2014 First Out Credit Facilities (Secured First Lien) | Federal fund rate
Debt
Interest rate added to variable rate basis (as a percent)									0.50%
2014 First Out Credit Facilities (Secured First Lien) | Quarters ending through June 30, 2017
Financial performance covenants
First-Lien First-Out Leverage Ratio, maximum								3.50	3.50
2014 First Out Credit Facilities (Secured First Lien) | Quarters ending through September 30, 2017
Financial performance covenants
First-Lien First-Out Leverage Ratio, maximum								3.25	3.25
2014 First Out Credit Facilities (Secured First Lien) | Quarters ending through December 31, 2017
Financial performance covenants
First-Lien First-Out Leverage Ratio, maximum								3.25	3.25
Minimum interest expense coverage ratio								1.20	1.20
2014 First Out Credit Facilities (Secured First Lien) | Quarters ending after first quarter of 2018
Financial performance covenants
First-Lien First-Out Leverage Ratio, maximum													2.25
Minimum interest expense coverage ratio								2.00	2.00
2014 First Out Credit Facilities (Secured First Lien) | Any June 30 and December 31 beginning after December 2016
Financial performance covenants
First-lien asset coverage ratio								1.20	1.20
2014 First Out Credit Facilities (Secured First Lien) | 5% Notes Due 2020
Debt
Threshold amount of remaining outstanding balance of debt above which prepayment on the 2014 First Out Credit Agreement accelerates								$ 100	$ 100
Financial performance covenants
Period before maturity of the specified notes									182 days
2016 Second Out Credit Agreement (Secured First Lien)
Debt
Outstanding borrowings								1,000	$ 1,000
Original issue discount								$ 10	$ 10
Percentage of premium to par value of coupon for make-whole premium									50.00%
2016 Second Out Credit Agreement (Secured First Lien) | Any June 30 and December 31 beginning after December 2016
Financial performance covenants
First-lien asset coverage ratio								1.20	1.20
2016 Second Out Credit Agreement (Secured First Lien) | 5% senior unsecured notes due January 15, 2020 (the 2020 Notes) and 5.50% senior unsecured notes due September 15, 2021 (the 2021 Notes)
Debt
Outstanding amount that triggers accelerated payment								$ 100	$ 100
Financial performance covenants
Period before maturity of the specified notes									91 days
Senior Notes (Secured Second Lien) | 8% Notes Due 2022
Debt
Interest rate (as a percent)					8.00%			8.00%	8.00%	8.00%
Outstanding borrowings					$ 2,250			$ 2,250	$ 2,250	$ 2,250
Financial performance covenants
Aggregate principal amount issued					2,250					$ 2,250
Senior Unsecured Notes
Debt
Principal amount of debt reduction through payment or repurchase							$ 100
Repurchase value of the principal amounts							13
Pre-tax gain on repurchase of debt					$ 560		$ 87
Financial performance covenants
Aggregate principal amount issued						$ 5,000
Net proceeds from private placement						4,950
Cash distribution to Occidental in October 2014						4,950
Percentage of principal amount at which senior notes can be redeemed									101.00%
Senior Unsecured Notes | 5% Notes Due 2020
Debt
Interest rate (as a percent)					5.00%			5.00%	5.00%	5.00%
Outstanding borrowings					$ 433			$ 193	$ 193	$ 433
Principal amount of debt reduction through payment or repurchase			$ 197		$ 534					$ 534
Financial performance covenants
Aggregate principal amount issued						1,000
Senior Unsecured Notes | 5.5% Notes Due 2021
Debt
Interest rate (as a percent)					5.50%			5.50%	5.50%	5.50%
Outstanding borrowings					$ 829			$ 135	$ 135	$ 829
Principal amount of debt reduction through payment or repurchase			605		$ 921					$ 921
Financial performance covenants
Aggregate principal amount issued						$ 1,750
Senior Unsecured Notes | 6% Notes Due 2024
Debt
Interest rate (as a percent)					6.00%	6.00%		6.00%	6.00%	6.00%
Outstanding borrowings					$ 892			$ 193	$ 193	$ 892
Principal amount of debt reduction through payment or repurchase			613		1,358					1,358
Financial performance covenants
Aggregate principal amount issued						$ 2,250
Senior Unsecured Notes | 5.50% Notes Due 2021 and 6.00% Notes Due 2024
Debt
Principal amount of debt reduction through payment or repurchase								11	11
Repurchase value of the principal amounts								6	$ 6
Pre-tax gain on repurchase of debt								$ 4
Minimum | 2014 First Out Credit Facilities (Secured First Lien)
Debt
Approval percentage measured by total exposure of lenders for approval of increases in borrowing base								80.00%	80.00%
Financial performance covenants
Total leverage ratio									3.00
Minimum | 2014 First Out Credit Facilities (Secured First Lien) | LIBOR loans
Debt
Interest rate added to variable rate basis (as a percent)									2.50%
Minimum | 2014 First Out Credit Facilities (Secured First Lien) | Alternate Base Rate loans
Debt
Interest rate added to variable rate basis (as a percent)									1.50%
Maximum | 2014 First Out Credit Facilities (Secured First Lien) | LIBOR loans
Debt
Interest rate added to variable rate basis (as a percent)									3.50%
Maximum | 2014 First Out Credit Facilities (Secured First Lien) | Alternate Base Rate loans
Debt
Interest rate added to variable rate basis (as a percent)									2.50%
Term loan facility | 2014 First Out Credit Facilities (Secured First Lien)
Debt
Maximum borrowing capacity								$ 650	$ 650
Outstanding borrowings					1,000			650	650	1,000
Repayment of term loan									100
Prepayment of term loan									$ 250
Term loan facility | 2016 Second Out Credit Agreement (Secured First Lien) | LIBOR loans
Debt
Interest rate added to variable rate basis (as a percent)									10.375%
Floor rate (as a percent)									1.00%
Revolving credit facility | 2014 First Out Credit Facilities (Secured First Lien)
Debt
Maximum borrowing capacity								1,400	$ 1,400
Increase to maximum borrowing capacity with lender approval									250
Outstanding borrowings					$ 739			847	847	$ 739
Repayment of revolving credit facility									$ 740
Commitment fees on unused portion of the Revolving Credit Facility									0.50%
Revolving credit facility | Letter of Credit
Debt
Maximum borrowing capacity								400	$ 400
Revolving credit facility | Senior Unsecured Notes
Debt
Repurchase value of the principal amounts			750
Pre-tax gain on repurchase of debt			$ 660
Term loan and Revolving credit facility | 2014 First Out Credit Facilities (Secured First Lien)
Debt
Maximum borrowing capacity								$ 2,050	$ 2,050
Borrowing base												$ 2,300
May 2016 debt for equity exchange | Senior Unsecured Notes | 5.50% Notes Due 2021 and 6.00% Notes Due 2024
Debt
Pre-tax gain on repurchase of debt				$ 44
Financial performance covenants
Number of shares issued | shares				2,100
Original debt exchanged				$ 80
October 2016 debt exchange for equity | Senior Unsecured Notes | 5.50% Notes Due 2021 and 6.00% Notes Due 2024
Debt
Pre-tax gain on repurchase of debt		$ 8
Financial performance covenants
Original debt exchanged		$ 22
Number of shares issued for converted debt | shares		1,300