Derivatives and Other Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

Schedule of Detail for Level 1, 2 and 3 Derivatives

The following tables present the detail for Level 1, 2 and 3 derivatives (see additional Level 3 information in further tables below):

	2021				2020
Balance at December 31,	Assets		Liabilities		Assets		Liabilities
Level 1 derivative instruments	$	19	$	29	$	21	$	7
Level 3 derivative instruments		2		1,293		-		838
Total	$	21	$	1,322	$	21	$	845
Less: Current		14		274		21		103
Noncurrent	$	7	$	1,048	$	-	$	742

	2021						2020
Year ended December 31,	Unrealized loss recognized in Other comprehensive (loss) income			Realized loss reclassed from Other comprehensive (loss) income to earnings			Unrealized loss recognized in Other comprehensive (loss) income			Realized loss reclassed from Other comprehensive (loss) income to earnings
Level 1 derivative instruments	$	(28	)	$	(10	)	$	8		$	(19	)
Level 3 derivative instruments		(759	)		(279	)		(374	)		(88	)
Noncontrolling and equity interest (Level 2)		5			(6	)		21			1
Total	$	(782	)	$	(295	)	$	(345	)	$	(106	)

Schedule of Fair Values of Level 3 Derivative Instruments Outstanding

Level 3 derivative instruments outstanding as of December 31, 2021 are described in the table below:

Description	Designation	Contract Termination	Unobservable Inputs Impacting Valuation	Sensitivity to Inputs
Power contracts
Embedded derivative that indexes the price of power to the LME price of aluminum plus the Midwest premium	Cash flow hedge of forward sales of aluminum	March 2026 December 2029 February 2036	LME price, Midwest premium and MWh per year	Increase in LME price and/or the Midwest premium results in a higher cost of power and an increase to the derivative liability
Embedded derivative that indexes the price of power to the LME price of aluminum	Cash flow hedge of forward sales of aluminum	September 2027	LME price and MWh per year	Increase in LME price results in a higher cost of power and an increase to the derivative liability
Embedded derivative that indexes the price of power to the credit spread between the Company and the counterparty	Not designated	October 2028	Estimated credit spread	Wider credit spread results in a higher cost of power and increase in the derivative liability
Financial contract
Hedge power prices	Not designated	June 2026	LME price and power price	Lower prices in the power market or higher LME prices result in an increase in the derivative liability

Schedule of Quantitative Information for Level 3 Derivative Contracts

The following table presents quantitative information related to the significant unobservable inputs described above for Level 3 derivative instruments (megawatt hours in MWh):

	December 31, 2021		Unobservable Input	Unobservable Input Range
Asset Derivatives
Financial contracts	$	2	Interrelationship of	Electricity (per MWh)	2022: $41.30
(undesignated)			forward energy price, LME		2022: $47.44
			forward price and the	LME (per mt)	2022: $2,803
			Consumer Price Index		2022: $2,803
Power contract		—	MWh of energy needed to produce the forecasted	LME	2022: $2,803 2022: $2,808
			mt of aluminum	Midwest premium	2022: $0.3015 2022: $0.2915
				Electricity	Rate of 2 million MWh per year
Total Asset Derivatives	$	2
Liability Derivatives
Power contract	$	284	MWh of energy needed	LME (per mt)	2022: $2,803
			to produce the forecasted		2027: $2,287
			mt of aluminum	Electricity	Rate of 4 million MWh per year
Power contracts		1,006	MWh of energy needed to produce the forecasted mt of aluminum	LME (per mt)	2022: $2,803 2029: $2,364 2036: $2,660
				Midwest premium (per pound)	2022: $0.3015 2029: $0.2715 2036: $0.2715
				Electricity	Rate of 18 million MWh per year
Power contract (undesignated)	3		Estimated spread between the 30-year debt yield of Alcoa and the counterparty	Credit spread	1.30%: 30-year debt yield spread 4.10%: Alcoa (estimated) 2.80%: counterparty
Total Liability Derivatives	$	1,293

Schedule of Fair Values of Level 3 Derivative Instruments Recorded as Assets and Liabilities

The fair values of Level 3 derivative instruments recorded in the accompanying Consolidated Balance Sheet were as follows:

Asset Derivatives	December 31, 2021		December 31, 2020
Derivatives not designated as hedging instruments:
Current—financial contract	$	2	$	—
Total derivatives not designated as hedging instruments	$	2	$	—
Total Asset Derivatives	$	2	$	—
Liability Derivatives
Derivatives designated as hedging instruments:
Current—power contracts	$	262	$	94
Current—financial contract		—		1
Noncurrent—power contracts		1,028		720
Total derivatives designated as hedging instruments	$	1,290	$	815
Derivatives not designated as hedging instruments:
Current—embedded credit derivative	$	1	$	4
Noncurrent—embedded credit derivative		2		19
Total derivatives not designated as hedging instruments	$	3	$	23
Total Liability Derivatives	$	1,293	$	838

Schedule of Net Fair Values of Level 3 Derivative Instruments and Effect of Hypothetical Change (Increase or Decrease of 10%) in Market Prices or Rates

The following table shows the net fair values of the Level 3 derivative instruments at December 31, 2021 and the effect on these amounts of a hypothetical change (increase or decrease of 10%) in the market prices or rates that existed as of December 31, 2021:

	Fair value asset (liability)			Index change of + / -10%
Power contracts	$	(1,290	)	$	357
Embedded credit derivative		(3	)		1
Financial contract		2			7

Schedule of Reconciliation of Activity for Derivative Contracts

The following tables present a reconciliation of activity for Level 3 derivative instruments:

	Assets			Liabilities
2021	Financial contract			Power contracts			Financial contract			Embedded credit derivative
January 1, 2021	$	—		$	814		$	1		$	23
Total gains or losses included in:
Sales (realized)		—			(277	)		—			—
Cost of goods sold (realized)		(6	)		—			(8	)		—
Other expenses, net (unrealized/realized)		7			—			—			(20	)
Other comprehensive (loss) income (unrealized)		—			753			6			—
Other		1			—			1			—
December 31, 2021	$	2		$	1,290		$	—		$	3
Change in unrealized gains or losses included in earnings for    derivative instruments held at December 31, 2021:
Other expenses, net	$	5		$	—		$	(1	)	$	(19	)

	Assets			Liabilities
2020	Financial contract			Power contracts			Financial contract		Embedded credit derivative
January 1, 2020	$	74		$	598		$	—	$	17
Total gains or losses included in:
Sales (realized)		—			(74	)		—		—
Cost of goods sold (realized)		14			—			—		—
Other expenses, net (unrealized/realized)		—			—			—		7
Other comprehensive (loss) income (unrealized)		(83	)		290			1		—
Other		(5	)		—			—		(1	)
December 31, 2020	$	—		$	814		$	1	$	23
Change in unrealized gains or losses included in earnings for    derivative instruments held at December 31, 2020:
Other, net	$	—		$	—		$	—	$	11

Schedule of Carrying Values and Fair Values of Other Financial Instruments

The carrying values and fair values of Alcoa Corporation’s other financial instruments were as follows:

	2021				2020
December 31,	Carrying value		Fair value		Carrying value		Fair value
Cash and cash equivalents	$	1,814	$	1,814	$	1,607	$	1,607
Restricted cash		110		110		3		3
Short-term borrowings		75		75		77		77
Long-term debt due within one year		1		1		2		2
Long-term debt, less amount due within one year		1,726		1,865		2,463		2,692