Debt instrument covenant interest expense coverage ratio.

No definition available.

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- Definition

Debt instrument covenant leverage ratio.

+ References

No definition available.

+ Details

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- Definition

Debt instrument covenant leverage ratio, possible increase.

+ References

No definition available.

+ Details

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- Definition

Debt instrument maturity year.

+ References

No definition available.

+ Details

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Balance Type:	na
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- Definition

Debt instrument redemption period.

+ References

No definition available.

+ Details

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- Definition

Line of credit facility maximum additional borrowing capacity.

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Date the debt agreement requires the first payment to be made, in CCYY-MM-DD format.

+ References

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- Definition

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

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
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Balance Type:	credit
Period Type:	instant

- Definition

Description of the frequency of periodic payments (monthly, quarterly, annual).

+ References

+ Details

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Period Type:	duration

- Definition

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

+ References

+ Details

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Period Type:	instant

- Definition

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.

+ References

No definition available.

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- Definition

Description of debt redemption features under terms of the debt agreement.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph e
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

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- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

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- Definition

Amount of contribution received by defined benefit plan from employer which increases plan assets.

+ References

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Balance Type:	debit
Period Type:	duration

- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

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Balance Type:	credit
Period Type:	duration

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

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-SubTopic 10
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+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	credit
Period Type:	instant

- Definition

Amount of the fee for available but unused credit capacity under the credit facility.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of increase (decrease) of the credit facility.

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-Name Accounting Standards Codification
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-Section S99
-Paragraph 1
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash outflow for the settlement of long-term borrowing, with the highest claim on the assets of the entity in case of bankruptcy or liquidation, as it matures.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3291-108585

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Period Type:	duration

- Definition

The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
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Balance Type:	debit
Period Type:	duration

- Definition

The cash inflow from a contractual arrangement with the lender, including letter of credit, standby letter of credit and revolving credit arrangements, under which borrowings can be made up to a specific amount at any point in time with maturities due beyond one year or the operating cycle, if longer.

+ References

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Period Type:	duration

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- Details

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Period Type:

- Details

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Debt - Additional Information (Detail) - USD ($)					1 Months Ended	3 Months Ended
Debt - Additional Information (Detail) - USD ($)	Apr. 07, 2021	Apr. 01, 2021	Mar. 04, 2021	Mar. 03, 2021	Mar. 31, 2021	Jun. 30, 2021	Mar. 31, 2021
Subsequent Event [Member]
Debt Instrument [Line Items]
U.S. defined benefit pension plans, company's contribution		$ 500,000,000
5.500% Senior Notes due 2027 [Member] \| Alcoa Nederland Holding BV [Member]
Debt Instrument [Line Items]
Debt redemption description							ANHBV has the option to redeem the 2029 Notes on at least 10 days, but not more than 60 days, prior notice to the holders of the 2029 Notes under multiple scenarios, including, in whole or in part, at any time or from time to time after March 31, 2024, at a redemption price specified in the indenture (up to 102.063% of the principal amount plus any accrued and unpaid interest in each case). Also, the 2029 Notes are subject to repurchase upon the occurrence of a change in control repurchase event (as defined in the indenture) at a repurchase price in cash equal to 101% of the aggregate principal amount of the 2029 Notes repurchased, plus any accrued and unpaid interest on the 2029 Notes repurchased.
4.125% Senior Notes due 2029 [Member] \| Alcoa Nederland Holding BV [Member]
Debt Instrument [Line Items]
Senior notes, interest percentage					4.125%		4.125%
Debt instrument maturity date					2029
Principal amount of debt					$ 500,000,000		$ 500,000,000
Proceeds from issuance of debt					$ 493,000,000
Debt instrument, frequency of periodic payment							semi-annually
Debt instrument, date of first required payment					Sep. 30, 2021
4.125% Senior Notes due 2029 [Member] \| Alcoa Nederland Holding BV [Member] \| Subsequent Event [Member]
Debt Instrument [Line Items]
U.S. defined benefit pension plans, company's contribution		$ 500,000,000
6.75% Notes, due 2024 [Member] \| Forecast [Member]
Debt Instrument [Line Items]
Loss on extinguishment of debt						$ 32,000,000
6.75% Notes, due 2024 [Member] \| Subsequent Event [Member]
Debt Instrument [Line Items]
Debt instrument maturity date	2024
Debt instrument redemption price percentage	103.375%
Redemption of senior note	$ 750,000,000
6.75% Notes, due 2024 [Member] \| Alcoa Nederland Holding BV [Member]
Debt Instrument [Line Items]
Senior notes, interest percentage					6.75%		6.75%
Debt instrument maturity date					2024
Principal amount of debt					$ 750,000,000		$ 750,000,000
Maximum [Member] \| 5.500% Senior Notes due 2027 [Member] \| Alcoa Nederland Holding BV [Member] \| After June 15, 2023 [Member]
Debt Instrument [Line Items]
Debt instrument redemption period							60 days
Debt instrument redemption price percentage							102.063%
Maximum [Member] \| 5.500% Senior Notes due 2027 [Member] \| Alcoa Nederland Holding BV [Member] \| Change in Control [Member]
Debt Instrument [Line Items]
Debt instrument redemption price percentage							101.00%
Maximum [Member] \| 6.75% Notes, due 2024 [Member] \| Subsequent Event [Member]
Debt Instrument [Line Items]
Debt instrument redemption price percentage	103.375%
Minimum [Member] \| 5.500% Senior Notes due 2027 [Member] \| Alcoa Nederland Holding BV [Member] \| After June 15, 2023 [Member]
Debt Instrument [Line Items]
Debt instrument redemption period							10 days
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum additional borrowings			$ 750,000,000		1,687,000,000		$ 1,687,000,000
Line of credit facility, outstanding borrowings			$ 1,500,000,000		$ 0		0
Amounts borrowed under the credit facility							0
Revolving Credit Facility [Member] \| 5.500% Senior Notes due 2027 [Member]
Debt Instrument [Line Items]
Line of credit facility, decrease in aggregate amount of commitments							245,000,000
Line of credit facility, aggregate amount of commitments							$ 1,255,000,000
Senior notes, interest percentage					5.50%		5.50%
Debt instrument maturity date							2027
Revolving Credit Facility [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio			275.00%	250.00%
Leverage ratio, maximum possible increase			300.00%
Revolving Credit Facility [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Interest expense coverage ratio required to be maintained			4.00	5.00