Derivatives and Other Financial Instruments - Schedule of Reconciliation of Activity for Derivative Contracts (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Financial Contracts [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value measurement, Assets, Beginning balance		$ 74
Other comprehensive (loss) income (unrealized)		(83)
Fair value measurement, Assets, Other	$ 1	(5)
Fair value measurement, Assets, Ending balance	2
Fair value measurement, Liabilities, Beginning balance	1
Fair value measurement, Liabilities, Cost of goods sold	(8)
Other comprehensive (loss) income (unrealized)	6	1
Fair value measurement, Liabilities, Other	1
Fair value measurement, Liabilities, Ending balance		1
Financial Contracts [Member] | Cost of Goods Sold [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value measurement, Assets	(6)	14
Financial Contracts [Member] | Other Expenses Net [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value measurement, Assets	7
Financial Contracts [Member] | Other (Income) Expenses, Net [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value measurement, Assets	5
Fair value measurement, Liabilities, Other expenses, net	(1)
Power Contract [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value measurement, Liabilities, Beginning balance	814	598
Other comprehensive (loss) income (unrealized)	753	290
Fair value measurement, Liabilities, Ending balance	1,290	814
Power Contract [Member] | Sales [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value measurement, Liabilities	(277)	(74)
Embedded Credit Derivative [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value measurement, Liabilities, Beginning balance	23	17
Fair value measurement, Liabilities, Other		(1)
Fair value measurement, Liabilities, Ending balance	3	23
Embedded Credit Derivative [Member] | Other Expenses Net [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value measurement, Liabilities	(20)	7
Embedded Credit Derivative [Member] | Other (Income) Expenses, Net [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value measurement, Liabilities, Other expenses, net	$ (19)	$ 11