DERIVATIVES - ADDITIONAL INFORMATION (Details) - USD ($)		1 Months Ended	5 Months Ended	12 Months Ended
		Aug. 31, 2019	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Feb. 27, 2020	Jan. 31, 2020	Oct. 31, 2019	Aug. 08, 2019
Derivative [Line Items]
Unrealized gains (losses) on derivatives	[1]			$ (129,000,000)	$ (6,000,000)	$ 13,000,000
Not designated as hedging instruments
Derivative [Line Items]
Aggregate fair value of derivative instruments with credit-risk-related contingent features for which a net liability position existed (net of collateral)			$ 787,000,000	787,000,000	68,000,000
Amount of collateral posted related to derivative instruments with credit-risk-related contingent features			169,000,000	169,000,000	$ 1,000,000
Anadarko Petroleum Corporation
Derivative [Line Items]
Debt instrument issued										$ 21,800,000,000
Anadarko Petroleum Corporation | Senior notes
Derivative [Line Items]
Debt instrument issued										$ 13,000,000,000.0
Anadarko Petroleum Corporation | Common Stock
Derivative [Line Items]
Exercise price of warrant (usd per share)										$ 62.50
Interest Rate Swap, 6.835%
Derivative [Line Items]
Notional Principal Amount			125,000,000	125,000,000					$ 125,000,000
Interest Rate Swap, 6.835% | Subsequent Event
Derivative [Line Items]
Notional Principal Amount							$ 150,000,000
Interest Rate Swap, 6.570%
Derivative [Line Items]
Notional Principal Amount			250,000,000	$ 250,000,000
Interest Rate Swap, 6.570% | Subsequent Event
Derivative [Line Items]
Notional Principal Amount								$ 500,000,000
Warrant
Derivative [Line Items]
Initial fair value of warrant										$ 188,000,000
Interest Rate Contract
Derivative [Line Items]
Net cash receipts related to settlements			$ 120,000,000
Unrealized gains (losses) on derivatives		$ (125,000,000)
Interest Rate Contract | Senior notes
Derivative [Line Items]
Debt instrument issued		$ 13,000,000,000.0

[1] Net of tax of $36, $2 and $(7) in 2019, 2018 and 2017, respectively.