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Debt Instrument, Covenant, Minimum Consolidated Net Income For Three Consecutive Calendar Months

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Period for borrowing funds.

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Amount of capital lease obligation due within one year or the normal operating cycle, if longer.

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Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days.

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Face (par) amount of the original debt instrument that was repurchased.

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Amount of unamortized debt discount (premium) and debt issuance costs.

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Gross amount of debt extinguished.

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Present value of lessee's discounted obligation for lease payments from finance lease, classified as current.

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The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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DEBT AND FINANCING COSTS - Additional Information (Detail)		1 Months Ended		3 Months Ended		9 Months Ended
	Jun. 21, 2019 USD ($)	Mar. 31, 2019	Nov. 30, 2018 USD ($) contract	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 GBP (£)	Jun. 19, 2019 USD ($)	Mar. 01, 2019 USD ($)	Feb. 28, 2019 USD ($)	Dec. 31, 2018 USD ($)	Mar. 31, 2018 USD ($)
Debt Instrument [Line Items]
Finance lease obligations, current				$ 19,000,000		$ 19,000,000
Current debt outstanding amount				19,000,000		19,000,000						$ 151,000,000
Capital lease obligations, current												1,000,000
Loss on extinguishment of debt				0	$ 94,000,000	75,000,000	$ 94,000,000
Available commercial paper				3,500,000,000		3,500,000,000
Commercial paper outstanding				0		0
Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit facility, committed amount													$ 4,000,000,000.0
Extended financing agreement term		1 year
Letters of credit outstanding, amount				0		0
Letter of Credit
Debt Instrument [Line Items]
Line of credit facility, committed amount				2,080,000,000.00		2,080,000,000.00
Credit facility maximum borrowing capacity				3,000,000,000.0		3,000,000,000.0
Line of credit facility aggregate commitment amount \| £								£ 3,100,000
Senior Notes \| 7.625% Senior Notes Due July 1, 2019
Debt Instrument [Line Items]
Current debt outstanding amount												$ 150,000,000
Debt instrument, stated interest rate												7.625%
Unsecured Debt
Debt Instrument [Line Items]
Debt instrument, face amount									$ 1,000,000,000.0
Unsecured Debt \| 4.250% Notes Due January 15, 2030
Debt Instrument [Line Items]
Debt instrument, stated interest rate									4.25%
Debt instrument, face amount									$ 600,000,000
Unsecured Debt \| 5.350% Notes Due July 1, 2049
Debt Instrument [Line Items]
Debt instrument, stated interest rate									5.35%
Debt instrument, face amount									$ 400,000,000
Altus Midstream LP \| Line of Credit
Debt Instrument [Line Items]
Borrowing amount				235,000,000		235,000,000						$ 0
Altus Midstream LP \| Line of Credit \| Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit facility, committed amount			$ 650,000,000							$ 1,500,000,000	$ 800,000,000
Extended financing agreement term			1 year
Letters of credit outstanding, amount				0		0						0
Line of credit facility, number of extension options \| contract			2
Debt covenant, minimum consolidated net income for three consecutive calendar months			$ 175,000,000
Borrowing amount				$ 235,000,000		$ 235,000,000						$ 0
Altus Midstream LP \| Line of Credit \| Letter of Credit
Debt Instrument [Line Items]
Line of credit facility, committed amount											100,000,000
Altus Midstream LP \| Line of Credit \| Swingline Loan Subfacility
Debt Instrument [Line Items]
Line of credit facility, committed amount											$ 100,000,000
Commercial Paper
Debt Instrument [Line Items]
Period for borrowing funds						270 days
Senior Notes
Debt Instrument [Line Items]
Debt repurchased principal amount	$ 932,000,000
Extinguishment of debt amount	1,000,000,000.0
Loss on extinguishment of debt	75,000,000
Unamortized debt issuance costs and discount	$ 7,000,000
Maximum \| Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit facility, committed amount													$ 5,000,000,000.0