Financial Risk Management Activities - Fair Values of Financial Risk Management Derivative Instruments (Detail) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Derivatives, Fair Value [Line Items]
Assets - Gross fair value of derivative contracts	$ 64	$ 157
Liabilities - Gross fair value of derivative contracts	(2)	(1)
Assets - Gross amounts offset in the Consolidated Balance Sheet	0	0
Liabilities - Gross amounts offset in the Consolidated Balance Sheet	0	0
Derivative assets	64	157
Derivative liabilities	(2)	(1)
Derivative Contracts Designated as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Assets - Gross fair value of derivative contracts	64	157
Liabilities - Gross fair value of derivative contracts	(2)	0
Derivative Contracts Designated as Hedging Instruments: \| Commodity Options / Collars
Derivatives, Fair Value [Line Items]
Assets - Gross fair value of derivative contracts	64	155
Liabilities - Gross fair value of derivative contracts	0	0
Derivative Contracts Designated as Hedging Instruments: \| Interest Rate Swaps
Derivatives, Fair Value [Line Items]
Assets - Gross fair value of derivative contracts	0	2
Liabilities - Gross fair value of derivative contracts	(2)	0
Derivative Contracts Not Designated as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Assets - Gross fair value of derivative contracts	0	0
Liabilities - Gross fair value of derivative contracts	0	(1)
Derivative Contracts Not Designated as Hedging Instruments: \| Foreign Exchange Forwards / Swaps
Derivatives, Fair Value [Line Items]
Assets - Gross fair value of derivative contracts	0	0
Liabilities - Gross fair value of derivative contracts	$ 0	$ (1)

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