Novelis (NVL) 10-Q 7 Aug 14 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Jun. 30, 2014	Aug. 06, 2014
Document and Entity Information [Abstract]	'	'
Entity Registrant Name	'Novelis Inc.	'
Entity Central Index Key	'0001304280	'
Document Type	'10-Q	'
Document Period End Date	30-Jun-14	'
Amendment Flag	'false	'
Document Fiscal Year Focus	'2015	'
Document Fiscal Period Focus	'Q1	'
Current Fiscal Year End Date	'--03-31	'
Entity Filer Category	'Non-accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	1,000

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (Unaudited) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Income Statement [Abstract]	'	'
Net sales	$2,680	$2,401
Cost of goods sold (exclusive of depreciation and amortization)	2,329	2,098
Selling, general and administrative expenses	108	120
Depreciation and amortization	89	77
Research and development expenses	12	10
Interest expense and amortization of debt issuance costs	81	76
Loss (gain) on assets held for sale	11	0
Restructuring and impairment, net	6	9
Equity in net loss of non–consolidated affiliates	2	4
Other (income) expense, net	5	-10
Total expenses	2,621	2,384
Income (loss) before income taxes	59	17
Income tax provision (benefit)	24	3
Net income	35	14
Net income attributable to noncontrolling interests	0	0
Net income (loss) attributable to our common shareholder	$35	$14

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Statement of Comprehensive Income [Abstract]	'	'
Net income (loss) attributable to our common shareholder	$35	$14
Net income attributable to noncontrolling interests	0	0
Net income	35	14
Other comprehensive income (loss):	'	'
Currency translation adjustment attributable to our common shareholder	26	-2
Currency translation adjustment attributable to noncontrolling interests	1	-1
Currency translation adjustment	27	-3
Net change in fair value of effective portion of cash flow hedges attributable to our common shareholder	13	-46
Net change in fair value of effective portion of cash flow hedges attributable to noncontrolling interests	0	0
Net change in fair value of effective portion of cash flow hedges	13	-46
Net change in pension and other benefits attributable to our common shareholder	-13	6
Net change in pension and other benefits attributable to noncontrolling interests	0	0
Net change in pension and other benefits	-13	6
Other comprehensive income (loss) before income tax effect attributable to our common shareholder	26	-42
Other comprehensive income (loss) before income tax effect attributable to noncontrolling interests	1	-1
Other comprehensive income (loss) before income tax effect	27	-43
Income tax (benefit) provision related to items of other comprehensive income (loss) attributable to our common shareholder	-5	0
Income tax (benefit) provision related to items of other comprehensive income (loss) attributable to noncontrolling interests	0	0
Income tax (benefit) provision related to items of other comprehensive income (loss)	-5	0
Other comprehensive income (loss), net of tax, attributable to our common shareholder	31	-42
Other comprehensive income (loss), net of tax, attributable to noncontrolling interests	1	-1
Other comprehensive income (loss), net of tax	32	-43
Comprehensive income (loss) attributable to our common shareholder	66	-28
Comprehensive income (loss) attributable to noncontrolling interest	1	-1
Comprehensive income (loss)	$67	($29)

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (Unaudited) (USD $)	Jun. 30, 2014	Mar. 31, 2014	Jun. 30, 2013	Mar. 31, 2013
In Millions, unless otherwise specified
Current assets	'	'	'	'
Cash and cash equivalents	$337	$509	$249	$301
Accounts receivable, net	'	'	'	'
Accounts and Other Receivables, Net, Current	1,557	1,382	'	'
— related parties	61	54	'	'
Inventories	1,295	1,173	'	'
Prepaid expenses and other current assets	114	101	'	'
Fair value of derivative instruments	67	51	'	'
Deferred income tax assets	101	101	'	'
Assets held for sale	72	102	'	'
Total current assets	3,604	3,473	'	'
Property, plant and equipment, net	3,575	3,513	'	'
Goodwill	608	611	'	'
Intangible assets, net	626	640	'	'
Investment in and advances to non-consolidated affiliates	607	612	'	'
Fair value of derivative instruments, net of current portion	9	4	'	'
Deferred income tax assets	80	80	'	'
Other long-term assets	'	'	'	'
— third parties	183	173	'	'
— related parties	21	12	'	'
Total assets	9,304	9,114	'	'
Current liabilities	'	'	'	'
Current portion of long-term debt	95	92	'	'
Short-term borrowings	956	723	'	'
Accounts payable	'	'	'	'
— third parties	1,651	1,418	'	'
— related parties	56	53	'	'
Fair value of derivative instruments	65	60	'	'
Accrued expenses and other current liabilities	455	547	'	'
Accrued Expenses - Related Party	0	250	'	'
Deferred income tax liabilities	19	16	'	'
Liabilities of Assets Held-for-sale	0	11	'	'
Total current liabilities	3,297	3,170	'	'
Long-term debt, net of current portion	4,350	4,359	'	'
Deferred income tax liabilities	421	425	'	'
Accrued postretirement benefits	632	621	'	'
Other long-term liabilities	269	271	'	'
Total liabilities	8,969	8,846	'	'
Commitments and contingencies	'	'	'	'
Shareholder's equity	'	'	'	'
Common stock, no par value; unlimited number of shares authorized; 1,000 shares issued and outstanding as of December 31, 2012 and March 31, 2012	0	0	'	'
Additional paid-in capital	1,404	1,404	'	'
Accumulated deficit	-1,038	-1,073	'	'
Accumulated other comprehensive income	-60	-91	-310	-268
Total equity of our common shareholder	306	240	'	'
Noncontrolling interests	29	28	'	'
Total equity	335	268	'	'
Total liabilities and equity	$9,304	$9,114	'	'

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Statement of Financial Position [Abstract]	'	'
Allowances for accounts receivable	$4	$4
Common stock, par value	'	'
Common stock, shares authorized	'unlimited	'unlimited
Common stock, shares issued	1,000	1,000
Common stock, shares outstanding	1,000	1,000

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
OPERATING ACTIVITIES	'	'
Net income	$35	$14
Adjustments to determine net cash used in operating activities:	'	'
Depreciation and amortization	89	77
(Gain) loss on unrealized derivatives and other realized derivatives in investing activities, net	-8	23
Gain on assets held for sale	-11	0
Deferred income taxes	3	-76
Amortization of fair value adjustments	3	3
Equity in net loss of non–consolidated affiliates	2	4
Gain on foreign exchange remeasurement of debt	0	-2
Loss on sale of assets	1	1
Amortization of debt issuance costs and carrying value adjustment	6	6
Other, net	-1	-1
Changes in assets and liabilities including assets and liabilities held for sale (net of effects from divestitures):	'	'
Accounts receivable	-169	-29
Inventories	-116	12
Accounts payable	245	-149
Other current assets	-14	3
Other current liabilities	-84	13
Other noncurrent assets	-10	2
Other noncurrent liabilities	5	-3
Net cash used in operating activities	-24	-102
INVESTING ACTIVITIES	'	'
Capital expenditures	-138	-181
Proceeds from sales of assets, net of transaction fees	34	0
Outflows from investments in and advances to non–consolidated affiliates, net	16	0
Proceeds (outflows) from settlement of other undesignated derivative instruments, net	1	-6
Net cash used in investing activities	-119	-187
FINANCING ACTIVITIES	'	'
Proceeds from issuance of debt	105	42
Principal payments	-53	-17
Short–term borrowings, net	166	219
Return of capital to our common shareholder	250	0
Debt issuance costs	0	-7
Net cash (used in) provided by financing activities	-32	237
Net decrease in cash and cash equivalents	-175	-52
Effect of exchange rate changes on cash	3	0
Cash and cash equivalents — beginning of period	509	301
Cash and cash equivalents — end of period	$337	$249

Condensed_Consolidated_Stateme3

Condensed Consolidated Statement of Shareholder's Equity (Unaudited) (USD $)	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss) (AOCI)	Non-controlling interests [Member]
In Millions, except Share data, unless otherwise specified
Balance at Mar. 31, 2014	$268	$0	$1,404	($1,073)	($91)	$28
Balance, shares at Mar. 31, 2014	'	1,000	'	'	'	'
Increase (Decrease) in Stockholders' Equity	'	'	'	'	'	'
Net income (loss) attributable to our common shareholder	35	'	'	35	'	'
Net Income (Loss) Attributable to Noncontrolling Interest	0	'	'	'	'	0
Currency translation adjustment, net of tax provision of $0 included in AOCI	27	'	'	'	26	1
Change in fair value of effective portion of cash flow hedges, net of tax benefit of $8 included in AOCI	13	'	'	'	13	'
Change in pension and other benefits, net of tax provision of $11 included in AOCI	-8	'	'	'	-8	'
Balance at Jun. 30, 2014	$335	$0	$1,404	($1,038)	($60)	$29
Balance, shares at Jun. 30, 2014	'	1,000	'	'	'	'

Condensed_Consolidated_Stateme4

Condensed Consolidated Statement of Shareholder's Equity (Unaudited) (Parenthetical) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014
Tax provision on currency translation adjustment	$0
Tax benefit on change in fair value of cash flow hedges	0
Tax provision on change in pension and other benefits	5
Accumulated Other Comprehensive Income (Loss) (AOCI)	'
Tax provision on currency translation adjustment	0
Tax benefit on change in fair value of cash flow hedges	0
Tax provision on change in pension and other benefits	5
Non-controlling interests [Member]	'
Tax provision on currency translation adjustment	$0

Business_and_Summary_of_Signif

Business and Summary of Significant Accounting Policies	3 Months Ended
	Jun. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	'
	BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
	References herein to “Novelis,” the “Company,” “we,” “our,” or “us” refer to Novelis Inc. and its subsidiaries unless the context specifically indicates otherwise. References herein to “Hindalco” refer to Hindalco Industries Limited, our indirect parent company.
	Organization and Description of Business
	We produce aluminum sheet and light gauge products for use in the packaging market, which includes beverage and food can and foil products, as well as for use in the transportation, electronics, architectural and industrial product markets. We also have recycling operations in many of our plants to recycle post-consumer aluminum, such as used-beverage cans (UBCs) and post-industrial aluminum, such as class scrap. As of June 30, 2014, we had manufacturing operations in nine countries on four continents: North America, South America, Asia and Europe; through 24 operating facilities, including recycling operations in ten of these plants. In addition to aluminum rolled products plants, our South American businesses include primary aluminum smelting and power generation facilities.
	The accompanying unaudited condensed consolidated financial statements should be read in conjunction with our audited consolidated financial statements and accompanying notes in our Annual Report on Form 10-K for the year ended March 31, 2014 filed with the United States Securities and Exchange Commission (SEC) on May 16, 2014. Management believes that all adjustments necessary for the fair statement of results, consisting of normally recurring items, have been included in the unaudited condensed consolidated financial statements for the interim periods presented.
	Consolidation Policy
	Our condensed consolidated financial statements include the assets, liabilities, revenues and expenses of all wholly-owned subsidiaries and majority-owned subsidiaries over which we exercise control and entities in which we have a controlling financial interest or are deemed to be the primary beneficiary. We eliminate all significant intercompany accounts and transactions from our condensed consolidated financial statements.
	We use the equity method to account for our investments in entities that we do not control, but where we have the ability to exercise significant influence over operating and financial policies. Consolidated “Net income attributable to our common shareholder” includes our share of net income (loss) of these entities. The difference between consolidation and the equity method impacts certain of our financial ratios because of the presentation of the detailed line items reported in the consolidated financial statements for consolidated entities, compared to a two-line presentation of "Investment in and advances to non–consolidated affiliates" and "Equity in net loss of non-consolidated affiliates."
	Use of Estimates and Assumptions
	The preparation of our condensed consolidated financial statements in conformity with accounting principles generally accepted in the United States of America (GAAP) requires us to make estimates and assumptions. These estimates and assumptions affect the reported amounts of assets and liabilities and the disclosures of contingent assets and liabilities as of the date of the financial statements, and the reported amounts of revenues and expenses during the reporting periods. The principal areas of judgment relate to (1) the fair value of derivative financial instruments; (2) impairment of goodwill; (3) impairment of long lived assets and other intangible assets; (4) impairment of and assessment of consolidation of equity investments; (5) actuarial assumptions related to pension and other postretirement benefit plans; (6) tax uncertainties and valuation allowances; and (7) assessment of loss contingencies, including environmental and litigation liabilities. Future events and their effects cannot be predicted with certainty, and accordingly, our accounting estimates require the exercise of judgment. The accounting estimates used in the preparation of our condensed consolidated financial statements will change as new events occur, as more experience is acquired, as additional information is obtained and as our operating environment changes. We evaluate and update our assumptions and estimates on an ongoing basis and may employ outside experts to assist in our evaluations. Actual results could differ from our estimates.
	Recently Adopted Accounting Standards
	Effective for the first quarter of fiscal 2015, we adopted Financial Accounting Standards Board ASU No. 2013-11, Income Taxes (Topic 740): Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. The amendments in this update provide guidance on the presentation of unrecognized tax benefits and will better reflect the manner in which an entity would settle, at the reporting date, any additional income taxes that would result from the disallowance of a tax position when net operating loss carryforwards, similar tax losses, or tax credit carryforwards exist. The adoption of this standard had an insignificant impact on our consolidated financial position.
	Recently Issued Accounting Standards
	In March 2013, the FASB issued ASU No. 2013-05, Foreign Currency Matters (Topic 830): Parent's Accounting for the Cumulative Translation Adjustment upon Derecognition of Certain Subsidiaries or Groups of Assets within a Foreign Entity or of an Investment in a Foreign Entity. The amendments in this update provide clarification regarding the release of a cumulative translation adjustment into net income when a parent either sells a part or all of its investment in a foreign entity or no longer holds a controlling financial interest in a subsidiary or group of assets within a foreign entity. The guidance will be effective for annual reporting periods beginning after December 15, 2014, and interim periods within those annual periods. We will adopt this standard prospectively in our first quarter ending June 30, 2015 and our current accounting policies comply with this guidance. Therefore, this will not have a material impact to our historical financial statements.
	In April 2014, the FASB issued ASU No. 2014-08, Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity. The amendments in this update change the criteria for determining which disposals can be presented as discontinued operations and modify related disclosure requirements. Under the revised standard, a discontinued operation is (1) a component of an entity or group of components that has been disposed of by sale, disposed of other than by sale or is classified as held for sale that represents a strategic shift that has or will have a major effect on an entity’s operations and financial results or (2) an acquired business or nonprofit activity that is classified as held for sale on the date of the acquisition. The guidance is effective for annual periods beginning on or after December 15, 2014 and interim periods within that year. The guidance will be applied prospectively. Early adoption is permitted but only for disposals (or classifications as held for sale) that have not been reported in financial statements previously issued or available for issue. We will adopt this standard prospectively in our first quarter ending June 30, 2015 on future disposals. The accounting treatment and classification of future disposals under this new standard could differ from our current treatment and classification of disposals in our current consolidated financial statements.
	In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (ASC 606), which, when effective, will supersede the guidance in former ASC 605, Revenue Recognition. The new guidance requires entities to recognize revenue based on the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance is effective for annual periods beginning on or after December 31, 2016 and interim periods within that year. Early adoption is not permitted. We will adopt this standard in our first quarter ending June 30, 2017. We are currently evaluating the impact of this standard on our consolidated financial position and results of operations.

Restructuring_and_Impairment

Restructuring and Impairment	3 Months Ended
	Jun. 30, 2014
Restructuring and Related Activities [Abstract]	'
RESTRUCTURING AND IMPAIRMENT	'
	RESTRUCTURING AND IMPAIRMENT
	“Restructuring and impairment, net” for the three months ended June 30, 2014 and 2013 was $6 million and $9 million, respectively.
	The following table summarizes our restructuring liability activity and other impairment charges (in millions).
			Total restructuring			Other restructuring charges				Total restructuring charges			Other impairments (B)		Total
			liabilities			(A)									restructuring
															and impairments, net
	Balance as of March 31, 2014		$	47
	Expenses		6			$	—			$	6		$	—	$	6
	Cash payments		(7		)
	Balance as of June 30, 2014		$	46
	(A)	Other restructuring charges include period expenses that were not recorded through the restructuring liability and impairments related to a restructuring activity.
	(B)	Other impairment charges not related to a restructuring activity.
	As of June 30, 2014, $27 million of restructuring liabilities was classified as short-term and was included in "Accrued expenses and other current liabilities" and $19 million was classified as long-term and was included in "Other long-term liabilities" on our condensed consolidated balance sheet.
	North America
	The following table summarizes our restructuring activity for the North America segment by plan (in millions).
				Three Months Ended June 30,			Year Ended March 31,				Prior to April 1,
				2014			2014				2013
	Restructuring charges - North America
	Saguenay Plant Closure:
		Severance		$	—		$	—			$	5
		Fixed asset impairment (A)		—			—				28
		Other exit related costs		—			1				—
		Period expenses (A)		—			1				3
	Relocation of R&D operations to Kennesaw, Georgia
		Severance		—			1				11
		Relocation costs		—			1				—
		Period expenses (A)		—			1				—
	Total restructuring charges - North America			$	—		$	5			$	47
	Restructuring payments - North America
		Severance		$	—		$	(4	)
		Other		—			(2		)
	Total restructuring payments - North America			$	—		$	(6	)
	(A)     These charges were not recorded through the restructuring liability.
	In fiscal 2012, we closed our Saguenay Works facility and relocated our North America research and development operations to a new global research and technology facility in Kennesaw, Georgia. As of June 30, 2014, the restructuring liability for the North America segment was $4 million, which relates to $3 million of severance charges and $1 million of other exit related costs.
	Europe
	The following table summarizes our restructuring activity for the Europe segment by plan (in millions).
			Three Months Ended June 30,			Year Ended March 31,				Prior to April 1,
			2014			2014				2013
	Restructuring charges - Europe
	Business optimization
		Severance	$	3		$	26			$	16
		Pension settlement loss (A)	—			1				—
	Total restructuring charges - Europe		$	3		$	27			$	16
	Total restructuring payments - Europe
		Severance	$	(6	)	$	(18	)
		Other	—			(1		)
	Total restructuring payments - Europe		$	(6	)	$	(19	)
	(A)     These charges were not recorded through the restructuring liability.
	The business optimization actions include the shutdown of facilities, staff rationalization and other activities to optimize our business in Europe. As of June 30, 2014, the restructuring liability for the Europe segment was $15 million and relates to $14 million of severance charges and $1 million of environmental remediation liabilities and other costs.
	South America
	The following table summarizes our restructuring activity for the South America segment by plan (in millions).
			Three Months Ended June 30,			Year Ended March 31,				Prior to April 1,
			2014			2014				2013
	Restructuring charges - South America
	Non-core assets
		Severance	$	—		$	2			$	3
		Asset impairments (A)	—			—				1
		Contract termination and other	—			1				5
		Environmental charges	2			16				—
	Aratu plant closure
		Severance				—				7
		Asset impairments (A)	—			—				7
		Other exit costs	1			—				6
Total restructuring charges - South America		$	3		$	19			$	29
Restructuring payments - South America
	Severance	$	—		$	(4	)
	Other	(1		)	(4		)
Total restructuring payments - South America		$	(1	)	$	(8	)
(A)     These charges were not recorded through the restructuring liability.
The non-core asset charges, including the shut down of one of our primary aluminum smelter lines in Ouro Preto, Brazil, were recorded as we take steps in aligning our global strategy on the premium markets of beverage cans, automobiles, and specialty products. In fiscal 2011, we closed our primary aluminum smelter in Aratu, Brazil. For further information on environmental charges see, Note 16 – Commitments and Contingencies.
As of June 30, 2014, the restructuring liability for the South America segment was $26 million and relates to $19 million of environmental charges, $1 million of contract termination charges, and $6 million of other exit related costs.
Corporate
The following table summarizes our restructuring activity for the Corporate operations by plan (in millions).
		Three Months Ended June 30,			Year Ended March 31,				Prior to April 1,
		2014			2014				2013
Restructuring charges - Corporate
Relocation costs of global headquarters		$	—		$	—			$	5
Restructuring payments - Corporate
	Lease Termination Costs	$	—		$	(1	)
Total restructuring payments - Corporate		$	—		$	(1	)
The other relocation costs relate to lease termination costs incurred in the relocation of our global headquarters to a new facility in Atlanta, Georgia and contract termination fees. As of June 30, 2014, the restructuring liability for the Corporate segment was $1 million.

Inventories

Inventories	3 Months Ended
	Jun. 30, 2014
Inventory Disclosure [Abstract]	'
INVENTORIES	'
	INVENTORIES
	"Inventories" consist of the following (in millions).
		June 30,		March 31,
		2014		2014
	Finished goods	$	325	$	259
	Work in process	480		419
	Raw materials	372		382
	Supplies	118		113
	Inventories	$	1,295	$	1,173
	Certain amounts within the components of "Inventories" as of March 31, 2014 have been revised. The immaterial revision had no impact on total "Inventories" as presented in the historical footnote or consolidated balance sheet.

Assets_Held_For_Sale

Assets Held For Sale	3 Months Ended
	Jun. 30, 2014
Assets Held For Sale [Abstract]	'
ASSETS HELD FOR SALE	'
	ASSETS HELD FOR SALE
	We are focused on capturing the global growth we see in our premium product markets of beverage can, automotive and specialties. We continually analyze our product portfolio to ensure we are focused on growing in attractive market segments. The following transactions relate to exiting certain non-core operations and are steps in aligning our growth strategy on the premium product markets.
	In March 2014, we made a decision to sell our hydroelectric power generation operations, including our investment in the Consorcio Candonga joint venture, in Brazil. In April 2014, we entered into agreements to sell the hydroelectric generation operations and our share of the Consorcio Candonga joint venture to two separate parties. The sale is expected to take place within the next twelve months and is pending regulatory approval. The related assets of $72 million have been classified as "Assets held for sale" in our condensed consolidated balance sheets as of June 30, 2014. The estimated fair market value of the hydroelectric power assets is in excess of the net book value.
	In May 2014, we recognized a $4 million "Gain on assets held for sale" in the condensed consolidated statements of operations upon receipt of a non-refundable milestone payment related to a land and mining rights sale agreement in Brazil. We expect to receive an additional $4 million within this fiscal year.
	In June 2014, we sold our consumer foil operations in North America to a third party for $31 million in cash (exclusive of transaction fees), $1 million of which is classified as "Accounts receivable, net - third parties" in our condensed consolidated balance sheets. We recognized a $7 million "Gain on assets held for sale" in the condensed consolidated statements of operations in the three months ended June 30, 2014. As of March 31, 2014, these assets and liabilities were classified as "Assets held for sale" and "Liabilities held for sale" in our condensed consolidated balance sheets.
	The following table summarizes the carrying amounts of the major classes of assets and liabilities held for sale (in millions).
		June 30,		March 31,
		2014		2014
	Assets held for sale
	Accounts receivable	$	—	$	10
	Inventories	—		15
	Prepaid expenses and other current assets	—		1
	Property, plant and equipment, net	32		37
	Investment in and advances to non-consolidated affiliates	40		39
	Total assets held for sale	$	72	$	102
	Liabilities held for sale
	Accounts payable	$	—	$	4
	Accrued expenses and other current liabilities	—		7
	Total liabilities held for sale	$	—	$	11

Consolidation

Consolidation	3 Months Ended
	Jun. 30, 2014
Consolidation [Abstract]	'
CONSOLIDATION	'
	CONSOLIDATION
	Variable Interest Entities (VIE)
	The entity that has a controlling financial interest in a VIE is referred to as the primary beneficiary and consolidates the VIE. An entity is deemed to have a controlling financial interest and is the primary beneficiary of a VIE if it has both the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance and an obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE.
	We have a joint interest in Logan Aluminum Inc. (Logan) with Tri-Arrows Aluminum Inc. (Tri-Arrows). Logan processes metal received from Novelis and Tri-Arrows and charges the respective partner a fee to cover expenses. Logan is thinly capitalized and relies on the regular reimbursement of costs and expenses by Novelis and Tri-Arrows to fund its operations. This reimbursement is considered a variable interest as it constitutes a form of financing of the activities of Logan. Other than these contractually required reimbursements, we do not provide other material support to Logan. Logan’s creditors do not have recourse to our general credit.
	We have a majority voting right on Logan’s board of directors and have the ability to direct the majority of Logan’s production operations. We also have the ability to take the majority share of production and associated costs. These facts qualify Novelis as Logan’s primary beneficiary and this entity is consolidated for all periods presented. All significant intercompany transactions and balances have been eliminated.
	The following table summarizes the carrying value and classification of assets and liabilities owned by the Logan joint venture and consolidated in our condensed consolidated balance sheets (in millions). There are significant other assets used in the operations of Logan that are not part of the joint venture, as they are directly owned and consolidated by Novelis or Tri-Arrows.
		June 30,		March 31,
		2014		2014
	Assets
	Current assets
	Cash and cash equivalents	$	—	$	1
	Accounts receivable	39		38
	Inventories	45		42
	Prepaid expenses and other current assets	1		1
	Total current assets	85		82
	Property, plant and equipment, net	11		14
	Goodwill	12		12
	Deferred income taxes	65		63
	Other long-term assets	2		3
	Total assets	$	175	$	174
	Liabilities
	Current liabilities
	Accounts payable	$	25	$	26
	Accrued expenses and other current liabilities	13		13
	Total current liabilities	38		39
	Accrued postretirement benefits	144		141
	Other long-term liabilities	2		2
	Total liabilities	$	184	$	182

Investment_In_and_Advances_To_

Investment In and Advances To Non-Consolidated Affiliates and Related Party Transactions	3 Months Ended
	Jun. 30, 2014
Related Party Transactions [Abstract]	'
INVESTMENT IN AND ADVANCES TO NON CONSOLIDATED AFFILIATES AND RELATED PARTY TRANSACTIONS	'
	INVESTMENT IN AND ADVANCES TO NON-CONSOLIDATED AFFILIATES AND RELATED PARTY TRANSACTIONS
	Included in the accompanying condensed consolidated financial statements are transactions and balances arising from businesses we conduct with our non-consolidated affiliates, which we classify as related party transactions and balances.
	The following table summarizes the results of operations of our equity method affiliates in aggregate for the three months ended June 30, 2014 and 2013; and the nature and amounts of significant transactions that we had with our non-consolidated affiliates (in millions). The amounts in the table below are disclosed at 100% of the operating results of these affiliates.
		Three Months Ended June 30,
		2014			2013
	Net sales	$	138		$	131
	Costs and expenses related to net sales	146			127
	(Benefit) provision for taxes on income	(2		)	4
	Net loss	$	(6	)	$	—
	Purchase of tolling services from Aluminium Norf GmbH (Norf)	$	69		$	66
	The following table describes the period-end account balances that we had with these non-consolidated affiliates, shown as related party balances in the accompanying condensed consolidated balance sheets (in millions). We had no other material related party balances with non-consolidated affiliates.
		June 30,			March 31,
		2014			2014
	Accounts receivable-related parties	$	61		$	54
	Other long-term assets-related parties	$	21		$	12
	Accounts payable-related parties	$	56		$	53
	We earned less than $1 million of interest income on a loan due from a non-consolidated affiliate, Aluminium Norf GmbH (Alunorf), during the three months ended June 30, 2014 and three months ended June 30, 2013. We believe collection of the full receivable from Alunorf is probable; thus no allowance for loan loss was provided for this loan as of June 30, 2014 and March 31, 2014.
	We have guaranteed the indebtedness for a credit facility on behalf of Alunorf. The guarantee is limited to 50% of the outstanding debt, not to exceed 6 million euros. As of June 30, 2014, there were no amounts outstanding under our guarantee with Alunorf. We have also guaranteed the payment of early retirement benefits on behalf of Alunorf. As of June 30, 2014, this guarantee totaled $4 million (3 million euros).
	Transactions with Hindalco and AV Metals Inc.
	We occasionally have related party transactions with our parent company, Hindalco. During the three months ended June 30, 2014 and 2013, “Net sales” were less than $1 million between Novelis and our indirect parent. As of June 30, 2014 and March 31, 2014, there were no "Accounts receivable, net" outstanding related to transactions with Hindalco.
	On April 30, 2014, we paid a return of capital to our shareholder, AV Metals Inc., in the amount of $250 million, which was declared in March 2014. The $250 million return of capital was recorded as "Accrued expense and other current liabilities" as of March 31, 2014 in our condensed consolidated balance sheets.

Debt

Debt	3 Months Ended
	Jun. 30, 2014
Debt Disclosure [Abstract]	'
DEBT	'
	DEBT
	Debt consisted of the following (in millions).
		June 30, 2014												March 31, 2014
		Interest		Principal			Unamortized				Carrying			Principal			Unamortized				Carrying
		Rates (A)					Carrying  Value				Value						Carrying  Value				Value
							Adjustments										Adjustments
	Third party debt:
	Short term borrowings	3.58	%	$	956		$	—			$	956		$	723		$	—			$	723
	Novelis Inc.
	Floating rate Term Loan Facility, due March 2017	3.75	%	1,745			(19		)	(B)	1,726			1,749			(20		)	(B)	1,729
	8.375% Senior Notes, due December 2017	8.375	%	1,100			—				1,100			1,100			—				1,100
	8.75% Senior Notes, due December 2020	8.75	%	1,400			—				1,400			1,400			—				1,400
	Capital lease obligations, due through July 2017	3.64	%	10			—				10			11			—				11
	Novelis Korea Limited
	Loans, due December 2014 through December 2015 (KRW 162 billion)	3.58	%	160			—				160			155			—				155
	Novelis Switzerland S.A.
	Capital lease obligation, due through December 2019 (Swiss francs (CHF) 31 million)	7.5	%	35			(1		)	(C)	34			36			(1		)	(C)	35
	Novelis do Brasil Ltda.
	BNDES loans, due February 2015 through April 2021 (BRL 27 million)	6.29	%	12			(2		)	(D)	10			13			(2		)	(D)	11
	Other
	Other debt, due through December 2020	5.74	%	5			—				5			10			—				10
	Total debt			5,423			(22		)		5,401			5,197			(23		)		5,174
	Less: Short-term borrowings			(956		)	—				(956		)	(723		)	—				(723		)
	Current portion of long term debt			(95		)	—				(95		)	(92		)	—				(92		)
	Long-term debt, net of current portion			$	4,372		$	(22	)		$	4,350		$	4,382		$	(23	)		$	4,359
	(A)	Interest rates are the fixed or variable rates as specified in the debt instruments (not the effective interest rate) as of June 30, 2014, and therefore, exclude the effects of related interest rate swaps, accretion/amortization of fair value adjustments as a result of purchase accounting in connection with Hindalco's purchase of Novelis and accretion/amortization of debt issuance costs related to the debt exchange completed in fiscal 2009 and the series of refinancing transactions and additional borrowings we completed in fiscal 2011, 2012 and 2013. We present stated rates of interest because they reflect the rate at which cash will be paid for future debt service.
	(B)	Debt existing at the time of Hindalco's purchase of Novelis was recorded at fair value. In connection with a series of refinancing transactions, a portion of the historical fair value adjustments were allocated to the Term Loan Facility, resulting in carrying value adjustments on this debt obligation. The unamortized carrying value also includes an issuance discount.
	(C)	Debt existing at the time of Hindalco's purchase of Novelis was recorded at fair value resulting in carrying value adjustments to our capital lease obligations in Novelis Switzerland.
	(D)	The unamortized carrying value includes issuance discounts related to the difference resulting from the contractual rates of interest specified in the instruments that are lower than the market rates of interest upon issuance.
	Principal repayment requirements for our total debt over the next five years and thereafter (excluding unamortized carrying value adjustments and using exchange rates as of June 30, 2014 for our debt denominated in foreign currencies) are as follows (in millions).
	As of June 30, 2014	Amount
	Short-term borrowings and current portion of long-term debt due within one year	$	1,051
	2 years	126
	3 years	1,720
	4 years	1,109
	5 years	9
	Thereafter	1,408
	Total	$	5,423
	Senior Secured Credit Facilities
	As of June 30, 2014, the senior secured credit facilities consisted of (1) a $1.7 billion four year secured term loan credit facility (Term Loan Facility) and (2) a $1.0 billion five-year asset based loan facility (ABL Revolver) which has a provision that allows the facility to be increased by an additional $500 million. The Term Loan Facility interest rate is equal to LIBOR (with a floor of 1%) plus a spread of 2.75%, at all times.
	In May 13, 2013, we amended and extended our asset based loan facility (ABL Facility) by entering into a $1.0 billion, five-year, Senior Secured ABL Revolver bearing an interest rate of LIBOR plus a spread of 1.75% to 2.25% plus a prime spread of 0.75% to 1.25% based on excess availability. The ABL Revolver has a provision that allows the facility to be increased by an additional $500 million. The ABL Revolver has various customary covenants including maintaining a minimum fixed charge coverage ratio of 1.25 to 1 if excess availability is less than the greater of (1) $110 million and (2) 15% of the lesser of (a) the Credit Facility and (b) the borrowing base. The fixed charge coverage ratio will be equal to the ratio of (1) (a) ABL defined EBITDA less (b) maintenance capital expenditures less (c) cash taxes; to (2) (a) interest expense plus (b) scheduled principal payments plus (c) dividends to the Company's direct holding company to pay certain taxes, operating expenses and management fees and repurchases of equity interests from employees, officers and directors. The facility matures on May 13, 2018; provided that, in the event that any of the Notes or the ABL Revolver are outstanding (and not refinanced with a maturity date later than November 13, 2018) 90 days prior to their respective maturity dates, then the ABL Revolver will mature 90 days prior to the maturity date for the Notes or the Term Loan Facility; unless excess availability under the ABL Revolver is at least (i) 25% of the lesser of (x) the total ABL Revolver commitment and (y) the then applicable borrowing base and (ii) 20% of the lesser of (x) the total ABL Revolver commitment and (y) the then applicable borrowing base, and a minimum fixed charged ratio test of at least 1.25 to 1 is met.
	The senior secured credit facilities contain various affirmative covenants, including covenants with respect to our financial statements, litigation and other reporting requirements, insurance, payment of taxes, employee benefits and (subject to certain limitations) causing new subsidiaries to pledge collateral and guarantee our obligations. The senior secured credit facilities also include various customary negative covenants and events of default, including limitations on our ability to (1) make certain restricted payments, (2) incur additional indebtedness, (3) sell certain assets, (4) enter into sale and leaseback transactions, (5) make investments, loans and advances, (6) pay dividends or returns of capital and distributions beyond certain amounts, (7) engage in mergers, amalgamations or consolidations, (8) engage in certain transactions with affiliates, and (9) prepay certain indebtedness. Substantially all of our assets are pledged as collateral under the senior secured credit facilities. As of June 30, 2014, we were in compliance with the covenants in the Term Loan Facility and ABL Revolver.
	Short-Term Borrowings
	As of June 30, 2014, our short-term borrowings were $956 million, consisting of $710 million of loans under our ABL Revolver, $171 million in Novelis Brazil loans, $57 million (KRW 58 billion) in Novelis Korea loans, $17 million (VND 370 billion) in Novelis Vietnam loans and $1 million of other short term borrowings. The weighted average interest rate on our total short-term borrowings was 3.58% as of June 30, 2014 and March 31, 2014.
	As of June 30, 2014, $12 million of the ABL Revolver was utilized for letters of credit, and we had $278 million in remaining availability under the ABL Revolver.
	In May 2013, Novelis Korea entered into two revolving loan facilities. As of June 30, 2014, one of the facilities has a borrowing capacity of $22 million (KRW 23 billion) and bears an interest rate of the three month financial rate as published by the Korea Financial Investment Association plus a spread of 1.6%. The second facility has a borrowing capacity of $49 million (KRW 50 billion) and bears an interest rate tied to Korea's three month CD rate plus a spread of 1.25%. Both facilities mature in May 2015. As of June 30, 2014, we had $7 million (KRW 8 billion) outstanding under the first facility and no borrowings outstanding under the second revolving loan facility.
	In March 2014, Novelis Korea entered into a new committed credit line with a borrowing capacity of $59 million (KRW 60 billion). The new facility bears an interest rate of the three month Korean Interbank Offered Rate plus a spread of 1.25%. As of June 30, 2014, we had no borrowings outstanding under this loan facility. This facility matures in March 2015.
	In June 2014, Novelis Korea entered into two additional committed credit facilities. As of June 30, 2014, one of the facilities has a borrowing capacity of $30 million (KRW 30 billion) and bears an interest rate tied to Korea's three month CD rate plus a spread of 1.25%. The second committed credit facility has a borrowing capacity of $16 million (KRW 16 billion) and bears an interest rate of the three month financial rate as published by the Korea Financial Investment Association plus a spread of 1.6%. Both facilities mature in June 2015. As of June 30, 2014, we had no borrowings outstanding under these committed credit facilities.
	Senior Notes
	On December 17, 2010, we issued $1.1 billion in aggregate principal amount of 8.375% Senior Notes Due 2017 (the 2017 Notes) and $1.4 billion in aggregate principal amount of 8.75% Senior Notes Due 2020 (the 2020 Notes, and together with the 2017 Notes, the Notes).
	The Notes contain customary covenants and events of default that will limit our ability and, in certain instances, the ability of certain of our subsidiaries to (1) incur additional debt and provide additional guarantees, (2) pay dividends or return capital beyond certain amounts and make other restricted payments, (3) create or permit certain liens, (4) make certain asset sales, (5) use the proceeds from the sales of assets and subsidiary stock, (6) create or permit restrictions on the ability of certain of the Company's subsidiaries to pay dividends or make other distributions to the Company, (7) engage in certain transactions with affiliates, (8) enter into sale and leaseback transactions, (9) designate subsidiaries as unrestricted subsidiaries and (10) consolidate, merge or transfer all or substantially all of the our assets and the assets of certain of our subsidiaries. During any future period in which either Standard & Poor's Ratings Group, Inc. or Moody's Investors Service, Inc. have assigned an investment grade credit rating to the Notes and no default or event of default under the Indenture has occurred and is continuing, most of the covenants will be suspended. As of June 30, 2014, we were in compliance with the covenants in the Notes.
	Korean Bank Loans
	As of June 30, 2014, Novelis Korea had $160 million (KRW 162 billion) of outstanding long-term loans with various banks, of which $64 million is due within one year. One of the loans has a fixed interest rate of 3.61% and a maturity of December 2015 and all other loans have variable interest rates with base rates tied to Korea's 91-day CD rate plus an applicable spread ranging from 0.80% to 1.41% with maturity dates ranging from December 2014 to December 2015. The weighted average interest rate is 3.58% as of June 30, 2014.
	Brazil BNDES Loans
	Novelis Brazil entered into loan agreements with Brazil’s National Bank for Economic and Social Development (the BNDES loans) related to the plant expansion in Pindamonhangaba, Brazil (Pinda). As of June 30, 2014, we had $12 million (BRL 27 million) outstanding under the BNDES loan agreements at a current weighted average rate of 6.29% with maturity dates of February 2015 through April 2021. As of June 30, 2014 there are $3 million of BNDES loans due within one year.
	Other Long-term debt
	In December 2004, we entered into a 15-year capital lease obligation with Alcan for assets in Sierre, Switzerland, which has an interest rate of 7.5% and fixed quarterly payments of CHF 1.7 million, (USD $1.9 million). As of June 30, 2014, we had $35 million (CHF 31 million) outstanding under this capital lease.
	During fiscal 2013, Novelis Inc. entered into various five-year capital lease arrangements to upgrade and expand our information technology infrastructure. As of June 30, 2014, we had $10 million outstanding under these capital leases.
	As of June 30, 2014, we had $5 million of other capital lease obligations with due dates through December 2020.
	Interest Rate Swaps
	We use interest rate swaps to manage our exposure to changes in benchmark interest rates which impact our variable-rate debt. See Note 11- Financial Instruments and Commodity Contracts for further information about these interest rate swaps.

ShareBased_Compensation

Share-Based Compensation	3 Months Ended
	Jun. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
SHARE-BASED COMPENSATION	'
	SHARE-BASED COMPENSATION
	The Company's board of directors has authorized long term incentive plans (LTIPs), under which Hindalco stock appreciation rights (Hindalco SARs), Novelis stock appreciation rights (Novelis SARs), and phantom restricted stock units (RSUs) are granted to certain executive officers and key employees.
	The Hindalco SARs and Novelis SARs vest at a rate of 25% per year, subject to the achievement of an annual performance target, and expire 7 years from their original grant date. Each Hindalco SAR is to be settled in cash based on the difference between the market value of one Hindalco share on the date of grant and the market value on the date of exercise. Each Novelis SAR is to be settled in cash based on the difference between the fair value of one Novelis phantom share on the original date of grant and the fair value of a phantom share on the date of exercise. The amount of cash paid to settle Hindalco SARs and Novelis SARs are limited to two and a half or three times the target payout depending on the plan year. The Hindalco SARs and Novelis SARs do not transfer any shareholder rights in Hindalco or Novelis to a participant. The Hindalco SARs and Novelis SARs are classified as liability awards and are remeasured at fair value each reporting period until the SARs are settled.
	The performance criterion for vesting of both the Hindalco SARs and Novelis SARs is based on the actual overall Novelis operating EBITDA compared to the target established and approved each fiscal year. The minimum threshold for vesting each year is 75% of each annual target operating EBITDA. Given that the performance criterion is based on an earnings target in a future period for each fiscal year, the grant date of the awards for accounting purposes is generally not established until the performance criterion has been defined.
	The RSUs vest in full three years from the grant date, subject to continued employment with the Company, but are not subject to performance criteria. Each RSU is to be settled in cash equal to the market value of one Hindalco share. The payout on the RSUs is limited to three times the market value of one Hindalco share measured on the original date of grant. The RSUs are classified as liability awards and expensed over the requisite service period (three years) based on the Hindalco stock price as of each balance sheet date.
	On May 13, 2013, the Company's board of directors amended the long-term incentive plans for fiscal years 2010 - 2013 (FY 2010 Plan), fiscal years 2011- 2014 (FY 2011 Plan), fiscal years 2012 - 2015 (FY 2012 Plan) and fiscal years 2013 - 2016 (FY 2013 Plan). The amendment gave each participant the option to cancel a portion of their outstanding Hindalco SARs for a lump-sum cash payment and/or the issuance of new Novelis SARs. The remaining Hindalco SARs and the new Novelis SARs continue to vest according to the terms and conditions of the original grant.
	Total compensation expense related to Hindalco SARs, Novelis SARs, and RSUs under the plans for the respective periods is presented in the table below (in millions). These amounts are included in “Selling, general and administrative expenses” or "Cost of goods sold (exclusive of depreciation and amortization)" in our condensed consolidated statements of operations. As the performance criteria for fiscal years 2016, 2017 and 2018 have not yet been established, measurement periods for Hindalco SARs and Novelis SARs relating to those periods have not yet commenced. As a result, only compensation expense for vested and current year Hindalco SARs and Novelis SARs has been recorded.
		Three Months Ended June 30,
		2014			2013
	Total compensation expense	$	4		$	13
	The table below shows the RSUs activity for the three months ended June 30, 2014.
			Number of		Grant Date Fair		Aggregate
			RSUs		Value		Intrinsic
					(in Indian Rupees)		Value (USD
							in millions)
	RSUs outstanding as of March 31, 2014		4,490,860		120.42		$	11
	Granted		1,455,206		145.5		—
	Exercised		(682,361	)	191.98		—
	Forfeited/Cancelled		(80,833	)	143.19		—
	RSUs outstanding as of June 30, 2014		5,182,872		118.47		$	15
	The table below shows the Hindalco SARs activity for the three months ended June 30, 2014.
			Number of		Weighted		Weighted Average		Aggregate
			SARs		Average		Remaining		Intrinsic
					Exercise Price		Contractual Term		Value (USD
					(in Indian Rupees)		(in years)		in millions)
	SARs outstanding as of March 31, 2014		21,635,392		112.26		4.3		$	13
	Granted		4,868,698		145.5		7		—
	Exercised		(4,128,272	)	89.97		—		—
	Forfeited/Cancelled		(730,823	)	131.29		—		—
	SARs outstanding as of June 30, 2014		21,644,995		123.35		4.9		$	17
	SARs exercisable as of June 30, 2014		8,339,534		121.52		3.3		$	8
	The table below shows the Novelis SARs activity for the three months ended June 30, 2014.
			Number of		Weighted			Weighted Average		Aggregate
			SARs		Average			Remaining		Intrinsic
					Exercise Price			Contractual Term		Value (USD
					(in USD)			(In years)		in millions)
	SARs outstanding as of March 31, 2014		668,402		$	90.09		5.3		$	2
	Granted		376,173		94.4			7		—
	Exercised		(12,244	)	66.46			—		—
	Forfeited/Cancelled		(33,760	)	83.77			—		—
	SARs outstanding as of June 30, 2014		998,571		$	92.22		5.8		$	4
	SARs exercisable as of June 30, 2014		223,623		$	89		4.8		$	2
	The fair value of each unvested Hindalco SAR was estimated using the following assumptions:
			Three Months Ended June 30,
			2014		2013
	Risk-free interest rate		8.56% - 8.78%		7.63% - 7.75%
	Dividend yield		0.61	%	1.4	%
	Volatility		43% - 55%		39% - 52%
	The fair value of each unvested Novelis SAR was estimated using the following assumptions:
			Three Months Ended June 30,
			2014		2013
	Risk-free interest rate		1.21% - 2.10%		1.00% - 1.66%
	Dividend yield		—	%	—	%
	Volatility		30% - 43%		31% - 41%
	The fair value of each unvested Hindalco SAR was based on the difference between the fair value of a long call and a short call option. The fair value of each of these call options was determined using the Monte Carlo Simulation model. We used historical stock price volatility data of Hindalco on the National Stock Exchange of India to determine expected volatility assumptions. The risk-free interest rate is based on Indian treasury yields interpolated for a time period corresponding to the remaining contractual life. The forfeiture rate is estimated based on actual historical forfeitures. The dividend yield is estimated to be the annual dividend of the Hindalco stock over the remaining contractual lives of the Hindalco SARs. The value of each vested Hindalco SAR is remeasured at fair value each reporting period based on the excess of the current stock price over the exercise price, not to exceed the maximum payout as defined by the plans. The fair value of the Hindalco SARs is being recognized over the requisite performance and service period of each tranche, subject to the achievement of any performance criteria.
	The fair value of each unvested Novelis SAR was based on the difference between the fair value of a long call and a short call option. The fair value of each of these call options was determined using the Monte Carlo Simulation model. We used the historical volatility of comparable companies to determine expected volatility assumptions. The risk-free interest rate is based on U.S. treasury yields for a time period corresponding to the remaining contractual life. The forfeiture rate is estimated based on actual historical forfeitures of Hindalco SARs. The value of each vested Novelis SAR is remeasured at fair value each reporting period based on the percentage increase in the current Novelis phantom stock price over the exercise price, not to exceed the maximum payout as defined by the plans. The fair value of the Novelis SARs is being recognized over the requisite performance and service period of each tranche, subject to the achievement of any performance criteria.
	The cash payments made to settle SAR liabilities were $5 million and $13 million in the three months ended June 30, 2014, and 2013, respectively. Total cash payments made to settle RSUs were $2 million and $1 million in the three months ended June 30, 2014 and 2013, respectively. Unrecognized compensation expense related to the non-vested Hindalco SARs (assuming all future performance criteria are met) was $15 million, which is expected to be recognized over a weighted average period of 2.1 years. Unrecognized compensation expense related to the non-vested Novelis SARs (assuming all future performance criteria are met) was $17 million, which is expected to be recognized over a weighted average period of 2.2 years. Unrecognized compensation expense related to the RSUs was $10 million, which will be recognized over the remaining weighted average vesting period of 1.8 years.

Postretirement_Benefit_Plans

Postretirement Benefit Plans	3 Months Ended
	Jun. 30, 2014
Compensation and Retirement Disclosure [Abstract]	'
POSTRETIREMENT BENEFIT PLANS	'
	POSTRETIREMENT BENEFIT PLANS
	Our pension obligations relate to: (1) funded defined benefit pension plans in the U.S., Canada, Switzerland and the U.K.; (2) unfunded defined benefit pension plans in Germany; (3) unfunded lump sum indemnities payable upon retirement to employees in France, Malaysia and Italy; and (4) partially funded lump sum indemnities in South Korea. Our other postretirement obligations (Other Benefits, as shown in certain tables below) include unfunded health care and life insurance benefits provided to retired employees in the U.S., Canada and Brazil.
	Components of net periodic benefit cost for all of our significant postretirement benefit plans are shown in the tables below (in millions).
		Pension Benefit Plans						Other Benefit Plans
		Three Months Ended June 30,						Three Months Ended June 30,
		2014			2013			2014			2013
	Service cost	$	11		$	13		$	1		$	3
	Interest cost	17			16			1			2
	Expected return on assets	(17		)	(16		)	—			—
	Amortization — losses, net	6			5			2			1
	Amortization — prior service credit, net	(1		)	—			(10		)	—
	Termination benefits / curtailments	1			—			(2		)	—
	Net periodic benefit cost	$	17		$	18		$	(8	)	$	6
	The average expected long-term rate of return on plan assets is 6.1% in fiscal 2015.
	In June 2014, the Company amended its U.S. non-union retiree medical plan to extend retirees' option to participate in a Retiree Health Access Exchange (RHA). For calendar years 2014 through 2017, the Company will subsidize a portion of the retiree medical premium rates of the RHA. The Company will not provide a subsidy beginning in calendar year 2018. The amendment to the plan resulted in a plan remeasurement and recognition of prior service costs of approximately $11 million which will be amortized on a straight-line basis through December 31, 2017.
	Employer Contributions to Plans
	For pension plans, our policy is to fund an amount required to provide for contractual benefits attributed to service to date, and amortize unfunded actuarial liabilities typically over periods of 15 years or less. We also participate in savings plans in Canada and the U.S., as well as defined contribution pension plans in the U.S., U.K., Canada, Germany, Italy, Korea, Malaysia and Brazil. We contributed the following amounts to all plans (in millions).
		Three Months Ended June 30,
		2014			2013
	Funded pension plans	$	4		$	6
	Unfunded pension plans	1			2
	Savings and defined contribution pension plans	6			5
	Total contributions	$	11		$	13
	During the remainder of fiscal 2015, we expect to contribute an additional $30 million to our funded pension plans, $13 million to our unfunded pension plans and $16 million to our savings and defined contribution plans.

Currency_Gains_Losses

Currency (Gains) Losses	3 Months Ended
	Jun. 30, 2014
Foreign Currency [Abstract]	'
CURRENCY (GAINS) LOSSES	'
	CURRENCY (GAINS) LOSSES
	The following currency (gains) losses are included in “Other expense (income), net” in the accompanying condensed consolidated statements of operations (in millions).
		Three Months Ended June 30,
		2014			2013
	Loss (gain) on remeasurement of monetary assets and liabilities, net	$	11		$	(18	)
	Loss released from accumulated other comprehensive income	—			1
	(Gain) loss recognized on balance sheet remeasurement currency exchange contracts, net	(11		)	12
	Currency gains, net	$	—		$	(5	)
	The following currency gains (losses) are included in Accumulated other comprehensive loss (“AOCI”), net of tax and “Noncontrolling interests” in the accompanying condensed consolidated balance sheets (in millions).
		Three Months Ended June 30, 2014			Year Ended
					31-Mar-14
	Cumulative currency translation adjustment — beginning of period	$	90		$	(30	)
	Effect of changes in exchange rates	27			120
	Cumulative currency translation adjustment — end of period	$	117		$	90

Financial_Instruments_and_Comm

Financial Instruments and Commodity Contracts	3 Months Ended
	Jun. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
FINANCIAL INSTRUMENTS AND COMMODITY CONTRACTS	'
	FINANCIAL INSTRUMENTS AND COMMODITY CONTRACTS
	The gross fair values of our financial instruments and commodity contracts as of June 30, 2014 and March 31, 2014 are as follows (in millions):
		June 30, 2014
		Assets								Liabilities						Net Fair Value
		Current				Noncurrent (A)				Current			Noncurrent (A)			Assets/(Liabilities)
	Derivatives designated as hedging instruments:
	Cash flow hedges
	Aluminum contracts	$	—			$	—			$	(13	)	$	—		$	(13	)
	Currency exchange contracts	23				9				(7		)	(4		)	21
	Energy contracts	2				—				—			—			2
	Interest rate swaps	—				—				(1		)	—			(1		)
	Total derivatives designated as hedging instruments	$	25			$	9			$	(21	)	$	(4	)	$	9
	Derivatives not designated as hedging instruments
	Aluminum contracts	16				—				(29		)	—			(13		)
	Currency exchange contracts	26				—				(9		)	—			17
	Energy contracts	—				—				(6		)	(11		)	(17		)
	Total derivatives not designated as hedging instruments	42				—				(44		)	(11		)	(13		)
	Total derivative fair value	$	67			$	9			$	(65	)	$	(15	)	$	(4	)
		March 31, 2014
		Assets								Liabilities						Net Fair Value
		Current				Noncurrent (A)				Current			Noncurrent(A)			Assets/(Liabilities)
	Derivatives designated as hedging instruments:
	Cash flow hedges
	Aluminum contracts	$	4			$	—			$	(7	)	$	—		$	(3	)
	Currency exchange contracts	15				4				(13		)	(6		)	—
	Energy contracts	3				—				—			—			3
	Net investment hedges
	Currency exchange contracts	—				—				(1		)	—			(1		)
	Fair value hedges
	Aluminum contracts	—				—				(1		)	—			(1		)
	Total derivatives designated as hedging instruments	$	22			$	4			$	(22	)	$	(6	)	$	(2	)
	Derivatives not designated as hedging instruments:
	Aluminum contracts	19				—				(28		)	—			(9		)
	Currency exchange contracts	9				—				(3		)	—			6
	Energy contracts	1				—				(7		)	(13		)	(19		)
	Total derivatives not designated as hedging instruments	29				—				(38		)	(13		)	(22		)
	Total derivative fair value	$	51			$	4			$	(60	)	$	(19	)	$	(24	)
	(A)	The noncurrent portions of derivative assets and liabilities are included in “Other long-term assets-third parties” and in “Other long-term liabilities” respectively, in the accompanying condensed consolidated balance sheets.
	Aluminum
	We use derivative instruments to preserve our conversion margins and manage the timing differences associated with metal price lag. We sell short-term London Metals Exchange (LME) and Midwest transaction premium aluminum forward contracts to reduce our exposure to fluctuating metal prices associated with the period of time between the pricing of our purchases of inventory and the pricing of the sale of that inventory to our customers. We also purchase forward LME aluminum contracts simultaneous with our sales contracts with customers that contain fixed metal prices. These LME aluminum forward contracts directly hedge the economic risk of future metal price fluctuations to better match the selling price of the metal with the purchase price of the metal.
	Price risk exposure arises from commitments to sell aluminum in future periods at fixed prices. We identify and designate certain LME aluminum forward contracts as fair value hedges of the metal price risk associated with fixed price sales commitments that qualify as firm commitments. Such exposures do not extend beyond two years in length. We had 5 kt and 9 kt of outstanding aluminum forward purchase contracts designated as fair value hedges as of June 30, 2014 and March 31, 2014, respectively.
	The following table summarizes the amount of gain (loss) recognized on fair value hedges of metal price risk:
			Amount of Gain (Loss)
			Recognized on Changes in Fair Value
			Three Months Ended June 30,
			2014				2013
	Fair Value Hedges of Metal Price Risk
	Derivative Contracts		$	1			$	(3	)
	Designated Hedged Items		(1		)		3
	Net Ineffectiveness (A)		$	—			$	—
	(A)Effective portion is recorded in "Net sales" and net ineffectiveness in "Other expense (income), net"
	Price risk arises due to fluctuating aluminum prices between the time the sales order is committed and the time the order is shipped. We identify and designate certain LME aluminum forward purchase contracts as cash flow hedges of the metal price risk associated with our future metal purchases that vary based on changes in the price of aluminum. Such exposures do not extend beyond three years in length. We had 3 kt and 16 kt of outstanding aluminum forward purchase contracts designated as cash flow hedges as of June 30, 2014 and March 31, 2014, respectively.
	Price risk exposure arises due to the timing lag between the LME based pricing of raw material metal purchases and the LME based pricing of finished product sales. Price risk exposure also arises due to fixed costs associated with our smelter operations in South America. We identify and designate certain LME aluminum forward sales contracts as cash flow hedges of the metal price risk associated with our future metal sales that vary based on changes in the price of aluminum. Such exposures do not extend beyond two years in length. We had 262 kt and 222 kt of outstanding aluminum forward sales contracts designated as cash flow hedges as of June 30, 2014 and March 31, 2014, respectively.
	The remaining balance of our LME and Midwest transaction premium aluminum derivative contracts are not designated as accounting hedges. As of June 30, 2014 and March 31, 2014, we had 89 kt and 105 kt, respectively, of outstanding aluminum sales contracts not designated as hedges. The average duration of undesignated contracts is less than five months. The following table summarizes our notional amount (in kt).
		June 30,			March 31,
		2014			2014
	Hedge Type
	Purchase (Sale)
	Cash flow purchases	3			16
	Cash flow sales	(262	)		(222	)
	Fair value	5			9
	Not designated	(89	)		(105	)
	Total, net	(343	)		(302	)
Foreign Currency
We use foreign exchange forward contracts, cross-currency swaps and options to manage our exposure to changes in exchange rates. These exposures arise from recorded assets and liabilities, firm commitments and forecasted cash flows denominated in currencies other than the functional currency of certain operations.
We use foreign currency contracts to hedge expected future foreign currency transactions, which include capital expenditures. These contracts cover the same periods as known or expected exposures. We had total notional amounts of $582 million and $724 million in outstanding foreign currency forwards designated as cash flow hedges as of June 30, 2014 and March 31, 2014, respectively.
We use foreign currency contracts to hedge our foreign currency exposure to our net investment in foreign subsidiaries. We had $53 million and $61 million outstanding foreign currency forwards designated as net investment hedges as of June 30, 2014 and as of March 31, 2014, respectively.
As of June 30, 2014 and March 31, 2014, we had outstanding currency exchange contracts with a total notional amount of $767 million and $649 million, respectively, which were not designated as hedges. Contracts that represent the majority of notional amounts will mature during the second and third quarters of fiscal 2015.
Energy
We own an interest in an electricity swap which we formerly designated as a cash flow hedge of our exposure to fluctuating electricity prices. As of March 31, 2011, due to significant credit deterioration of our counterparty, we discontinued hedge accounting for this electricity swap. Less than 1 million of notional megawatt hours remained outstanding as of June 30, 2014, and the fair value of this swap was a liability of $17 million as of June 30, 2014. As of March 31, 2014, the fair value of this electricity swap was a liability of $19 million.
We use natural gas swaps to manage our exposure to fluctuating energy prices in North America. We had 8.1 million MMBTUs designated as cash flow hedges as of June 30, 2014, and the fair value of these swaps was an asset of $2 million. There were 9.5 million MMBTUs of natural gas swaps designated as cash flow hedges as of March 31, 2014 and the fair value of these swaps was an asset of $3 million. As of June 30, 2014 and March 31, 2014, we had 1.1 million MMBTUs and 1.5 million MMBTUs, respectively, of natural gas swaps that were not designated as hedges. The fair value as of June 30, 2014 and March 31, 2014 was an asset of less than $1 million, respectively, for the swaps not designated as hedges. The average duration of undesignated contracts is less than one year in length. One MMBTU is the equivalent of one decatherm, or one million British Thermal Units.
Interest Rate
As of June 30, 2014, we swapped $134 million (KRW 136 billion) floating rate loans to a weighted average fixed rate of 4.03%. All swaps expire concurrent with the maturity of the related loans. As of June 30, 2014 and March 31, 2014, $134 million (KRW 136 billion) and $127 million (KRW 136 billion) were designated as cash flow hedges, respectively.
Gain (Loss) Recognition
The following table summarizes the gains (losses) associated with the change in fair value of derivative instruments not designated as hedges and the ineffectiveness of designated derivatives recognized in “Other (income) expense, net” (in millions). Gains (losses) recognized in other line items in the condensed consolidated statement of operations are separately disclosed within this footnote.
	Three Months Ended June 30,
	2014				2013
Derivative instruments not designated as hedges
Aluminum contracts	$	(7	)		$	(2	)
Currency exchange contracts	12				(12		)
Energy contracts (A)	2				—
Gain (loss) recognized in "Other expense (income), net"	$	7			$	(14	)
Derivative instruments designated as hedges
Gain recognized in "Other expense (income), net" (B)	2				10
Total gain (loss) recognized in "Other expense (income), net"	$	9			$	(4	)
Balance sheet remeasurement currency exchange contracts	$	11			$	(13	)
Realized (losses) gains, net	(3		)		21
Unrealized gains (losses) on other derivative instruments, net	1				(12		)
Total gain (loss) recognized in "Other expense (income), net"	$	9			$	(4	)
(A)	Includes amounts related to de-designated electricity swap.
(B)	Amount includes: forward market premium/discount excluded and hedging relationship ineffectiveness on designated aluminum and foreign currency capex contracts; releases to income from AOCI on balance sheet remeasurement contracts; and ineffectiveness on fair value hedges involving aluminum derivatives.
The following table summarizes the impact on AOCI and earnings of derivative instruments designated as cash flow and net investment hedges (in millions). Within the next twelve months, we expect to reclassify $2 million of gains from AOCI to earnings, before taxes.
	Amount of Gain (Loss)								Amount of Gain (Loss)
	Recognized in OCI								Recognized in “Other (Income)
	(Effective Portion)								Expense, net” (Ineffective and
									Excluded Portion)
	Three Months Ended June 30,								Three Months Ended June 30,
	2014				2013				2014			2013
Cash flow hedging derivatives
Aluminum contracts	$	(21	)		$	29			$	3		$	11
Currency exchange contracts	32				(51		)		(1		)	—
Energy contracts (A)	—				(2		)		—			—
Total	$	11			$	(24	)		$	2		$	11
Gain (Loss) Reclassification
	Amount of Gain (Loss) Reclassified from AOCI into Income/(Expense) three months ended June 30,								Location of Gain (Loss)
									Reclassified from AOCI into
									Earnings
Cash flow hedging derivatives	2014				2013
Energy contracts (A)	$	(1	)		$	(1	)		Other expense (income), net
Energy contracts (C)	1				—				Cost of goods sold (B)
Aluminum contracts	(6		)		21				Cost of goods sold (B)
Aluminum contracts	—				2				Net sales
Currency exchange contracts	1				1				Cost of goods sold (B)
Currency exchange contracts	4				—				Net sales
Currency exchange contracts	1				(1		)		Other expense (income), net
Total	$	—			$	22			Income before taxes
	—				(7		)		Income tax provision
	$	—			$	15			Net income
(A)	Includes amounts related to de-designated electricity swap. AOCI related to this swap is amortized to income over the remaining term of the hedged item.
(B)	"Cost of goods sold" is exclusive of depreciation and amortization.
(C)	Includes amounts related to natural gas swaps.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income (Loss) Accumulated Other Comprehensive Income (Loss)	3 Months Ended
	Jun. 30, 2014
Equity [Abstract]	'
Comprehensive Income (Loss) Note [Text Block]	'
	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)
	The following tables summarize the change in the components of accumulated other comprehensive income (loss) net of tax, for the periods presented (in millions).
			Currency Translation				(A) Cash Flow Hedges				(B)			Total
											Postretirement Benefit Plans
	Balance as of March 31, 2014		$	89			$	(20	)		$	(160	)	$	(91	)
	Other comprehensive income before reclassifications		26				13				(5		)	34
	Amounts reclassified from AOCI, net		—				—				(3		)	(3		)
	Net current-period other comprehensive income (loss)		26				13				(8		)	31
	Balance as of June 30, 2014		$	115			$	(7	)		$	(168	)	$	(60	)
			Currency Translation				(A) Cash Flow Hedges				(B)			Total
											Postretirement Benefit Plans
	Balance as of March 31, 2013		$	(33	)		$	(2	)		$	(233	)	$	(268	)
	Other comprehensive income before reclassifications		(2		)		(29		)		—			(31		)
	Amounts reclassified from AOCI, net		—				(15		)		4			(11		)
	Net current-period other comprehensive income (loss)		(2		)		(44		)		4			(42		)
	Balance as of June 30, 2013		$	(35	)		$	(46	)		$	(229	)	$	(310	)
	(A)  For additional information on our cash flow hedges see Note 11 - Financial Instruments and Commodity Contracts.
	(B)	For additional information on our postretirement benefit plans see Note 9 - Postretirement Benefit Plans.
	The following table summarizes the impact on AOCI and earnings of derivative instruments designation as cash flow hedges (in millions).
		Amount of Gain (Loss) Reclassified from AOCI into Income/(Expense) three months ended June 30,								Location of Gain (Loss)
										Reclassified from AOCI into
										Earnings
	Cash flow hedging derivatives	2014				2013
	Energy contracts (A)	$	(1	)		$	(1	)		Other expense (income), net
	Energy contracts (C)	1				—				Cost of goods sold (B)
	Aluminum contracts	(6		)		21				Cost of goods sold (B)
	Aluminum contracts	—				2				Net sales
	Currency exchange contracts	1				1				Cost of goods sold (B)
	Currency exchange contracts	4				—				Net sales
	Currency exchange contracts	1				(1		)		Other expense (income), net
	Total	$	—			$	22			Income before taxes
		—				(7		)		Income tax provision
		$	—			$	15			Net income
	(A)	Includes amounts related to de-designated electricity swap. AOCI related to this swap is amortized to income over the remaining term of the hedged item.
	(B)	"Cost of goods sold" is exclusive of depreciation and amortization.
	(C)	Includes amounts related to natural gas swaps.

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Jun. 30, 2014
Fair Value Disclosures [Abstract]	'
FAIR VALUE MEASUREMENTS	'
	FAIR VALUE MEASUREMENTS
	We record certain assets and liabilities, primarily derivative instruments, on our condensed consolidated balance sheets at fair value. We also disclose the fair values of certain financial instruments, including debt and loans receivable, which are not recorded at fair value. Our objective in measuring fair value is to estimate an exit price in an orderly transaction between market participants on the measurement date. We consider factors such as liquidity, bid/offer spreads and nonperformance risk, including our own nonperformance risk, in measuring fair value. We use observable market inputs wherever possible. To the extent that observable market inputs are not available, our fair value measurements will reflect the assumptions we used. We grade the level of the inputs and assumptions used according to a three-tier hierarchy:
	Level 1 — Unadjusted quoted prices in active markets for identical, unrestricted assets or liabilities that we have the ability to access at the measurement date.
	Level 2 — Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly.
	Level 3 — Unobservable inputs for which there is little or no market data, which require us to develop our own assumptions based on the best information available as what market participants would use in pricing the asset or liability.
	The following section describes the valuation methodologies we used to measure our various financial instruments at fair value, including an indication of the level in the fair value hierarchy in which each instrument is generally classified.
	Derivative Contracts
	For certain derivative contracts that have fair values based upon trades in liquid markets, such as aluminum, foreign exchange and natural gas forward contracts and options, valuation model inputs can generally be verified and valuation techniques do not involve significant judgment. The fair values of such financial instruments are generally classified within Level 2 of the fair value hierarchy.
	The majority of our derivative contracts are valued using industry-standard models that use observable market inputs as their basis, such as time value, forward interest rates, volatility factors, and current (spot) and forward market prices. We generally classify these instruments within Level 2 of the valuation hierarchy. Such derivatives include interest rate swaps, cross-currency swaps, foreign currency contracts, LME and Midwest transaction premium aluminum forwards and swaps and natural gas forward contracts.
	We classify derivative contracts that are valued based on models with significant unobservable market inputs as Level 3 of the valuation hierarchy. Our electricity swap, which is our only Level 3 derivative contract, represents an agreement to buy electricity at a fixed price at our Oswego, New York facility. Forward prices are not observable for this market, so we must make certain assumptions based on available information that we believe to be relevant to market participants. We use observable forward prices for a geographically nearby market and adjust for 1) historical spreads between the cash prices of the two markets, and 2) historical spreads between retail and wholesale prices.
	The average forward price at June 30, 2014, estimated using the method described above, was $59 per megawatt hour, which represented an $8 premium over forward prices in the nearby observable market. The actual rate from the most recent swap settlement was approximately $51 per megawatt hour. Each $1 per megawatt hour decline in price decreases the valuation of the electricity swap by approximately $1 million.
	For Level 2 and 3 of the fair value hierarchy, where appropriate, valuations are adjusted for various factors such as liquidity, bid/offer spreads and credit considerations (nonperformance risk). We regularly monitor these factors along with significant market inputs and assumptions used in our fair value measurements and evaluate the level of the valuation input according to the fair value hierarchy.  This may result in a transfer between levels in the hierarchy from period to period. As of June 30, 2014 and March 31, 2014, we did not have any Level 1 derivative contracts. No amounts were transferred between levels in the fair value hierarchy.
	All of the Company's derivative instruments are carried at fair value in the statements of financial position prior to considering master netting agreements. The table below also discloses the net fair value of the derivative instruments after considering the impact of master netting agreements.
	The following tables present our derivative assets and liabilities which were measured and recognized at fair value on a recurring basis classified under the appropriate level of the fair value hierarchy as of June 30, 2014 and March 31, 2014 (in millions).
		June 30, 2014						March 31, 2014
		Assets			Liabilities			Assets			Liabilities
	Level 2 instruments
	Aluminum contracts	$	16		$	(42	)	$	23		$	(36	)
	Currency exchange contracts	58			(20		)	28			(23		)
	Energy contracts	2			—			4			(1		)
	Interest rate swaps	—			(1		)	—			—
	Total level 2 instruments	76			(63		)	55			(60		)
	Level 3 instruments
	Energy contracts	—			(17		)	—			(19		)
	Total level 3 instruments	—			(17		)	—			(19		)
	Total gross	$	76		$	(80	)	$	55		$	(79	)
	Netting adjustment (A)	(21		)	21			(20		)	20
	Total net	$	55		$	(59	)	$	35		$	(59	)
	(A) Amounts represent the impact of legally enforceable master netting agreements that allow the Company to settle positive and negative positions with the same counterparties.
	We recognized unrealized gains of less than $1 million for the three months ended June 30, 2014 related to Level 3 financial instruments that were still held as of June 30, 2014. These unrealized gains were included in “Other expense (income), net.”
	The following table presents a reconciliation of fair value activity for Level 3 derivative contracts (in millions).
		Level 3  –
		Derivative Instruments (A)
	Balance as of March 31, 2014	$	(19	)
	Realized/unrealized gain included in earnings (B)	4
	Settlements	(2		)
	Balance as of June 30, 2014	$	(17	)
	(A)    Represents net derivative liabilities.
	(B)    Included in “Other expense (income), net.”
	Financial Instruments Not Recorded at Fair Value
	The table below presents the estimated fair value of certain financial instruments that are not recorded at fair value on a recurring basis (in millions). The table excludes short-term financial assets and liabilities for which we believe carrying value approximates fair value. The fair value of long-term receivables is based on anticipated cash flows, which approximates carrying value and is classified as Level 2. We value long-term debt using Level 2 inputs. Valuations are based on either market and/or broker ask prices when available or on a standard credit adjusted discounted cash flow model.
		June 30, 2014						March 31, 2014
		Carrying			Fair			Carrying			Fair
		Value			Value			Value			Value
	Assets
	Long-term receivables from related parties	$	21		$	21		$	12		$	12
	Liabilities
	Total debt — third parties (excluding short term borrowings)	$	4,445		$	4,655		$	4,451		$	4,734

Other_Income_Expense_Net

Other (Income) Expense, Net	3 Months Ended
	Jun. 30, 2014
Other Income and Expenses [Abstract]	'
OTHER (INCOME) EXPENSE, NET	'
	OTHER EXPENSE (INCOME), NET
	“Other expense (income), net” is comprised of the following (in millions).
		Three Months Ended June 30,
		2014			2013
	Foreign currency remeasurement gains, net (A)	$	—		$	(5	)
	(Gain) loss on change in fair value of other unrealized derivative instruments, net	(1		)	12
	Loss (gain) on change in fair value of other realized derivative instruments, net	3			(21		)
	Loss on Brazilian tax litigation, net (B)	2			1
	Interest income	(1		)	(1		)
	Other, net	2			4
	Other expense (income), net	$	5		$	(10	)
	(A)	Includes “(Gain) loss recognized on balance sheet remeasurement currency exchange contracts, net.”
	(B)	See Note 16 – Commitments and Contingencies – Brazil Tax and Legal Matters for further details.

Income_Taxes

Income Taxes	3 Months Ended
	Jun. 30, 2014
Income Tax Disclosure [Abstract]	'
INCOME TAXES	'
	INCOME TAXES
	A reconciliation of the Canadian statutory tax rate to our effective tax rate was as follows (in millions, except percentages).
		Three Months Ended June 30,
		2014			2013
	Pre-tax income before equity in net income of non-consolidated affiliates and noncontrolling interests	$	61		$	21
	Canadian statutory tax rate	25		%	26		%
	Provision at the Canadian statutory rate	$	15		$	5
	Increase (decrease) for taxes on income (loss) resulting from:
	Exchange translation items	4			(9		)
	Exchange remeasurement of deferred income taxes	4			(15		)
	Change in valuation allowances	11			37
	Income items not subject to tax	(1		)	(1		)
	Dividends not subject to tax	(10		)	(14		)
	Tax rate differences on foreign earnings	1			—
	Income tax provision	$	24		$	3
	Effective tax rate	39		%	14		%
	The exchange remeasurement of deferred income taxes relates to deferred tax assets and liabilities in Brazil which get remeasured for currency fluctuations against the U.S. dollar. The change in valuation allowances primarily relates to tax losses in certain jurisdictions where we believe it is more likely than not that we will not be able to utilize those losses.
	As of June 30, 2014, we had a net deferred tax liability of $259 million. This amount included gross deferred tax assets of approximately $877 million and a valuation allowance of $429 million. It is reasonably possible that our estimates of future taxable income may change within the next 12 months, resulting in a change to the valuation allowance in one or more jurisdictions.
	Tax authorities continue to examine certain of our tax filings for fiscal years 2005 through 2013. As a result of audit settlements, judicial decisions, the filing of amended tax returns or the expiration of statutes of limitations, our reserves for unrecognized tax benefits, as well as reserves for interest and penalties, may decrease in the next 12 months by an amount up to approximately $3 million.

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Jun. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
COMMITMENTS AND CONTINGENCIES	'
	COMMITMENTS AND CONTINGENCIES
	We are party to, and may in the future be involved in, or subject to, disputes, claims and proceedings that arise in the ordinary course of our business, including some that we assert against others, such as environmental, health and safety, product liability, employee, tax, personal injury and other matters. We have established a liability with respect to contingencies for which a loss is probable and estimable. While the ultimate resolution of and liability and costs related to these matters cannot be determined with certainty, we do not believe that any of these pending actions, individually or in the aggregate, will materially impair our operations or materially affect our financial condition or liquidity.
	For certain matters in which the Company is involved, for which a loss is reasonably possible, we are unable to estimate a loss. For certain other matters for which a loss is reasonably possible and the loss is estimable, we have estimated the aggregated range of loss as $0 to $90 million. This estimated aggregate range of reasonably possible losses is based upon currently available information. The Company’s estimates involve significant judgment, and therefore, the estimate will change from time to time and actual losses may differ from the current estimate. We review the status of, and estimated liability related to, pending claims and civil actions on a quarterly basis. The evaluation model includes all asserted and unasserted claims that can be reasonably identified including claims relating to our responsibility for compliance with environmental, health and safety laws and regulations in the jurisdictions in which we operate or formerly operated. The estimated costs in respect of such reported liabilities are not offset by amounts related to insurance or indemnification arrangements unless otherwise noted.
	The following describes certain contingencies relating to our business, including those for which we assumed liability as a result of our spin-off from Alcan Inc.
	Environmental Matters
	We own and operate numerous manufacturing and other facilities in various countries around the world. Our operations are subject to environmental laws and regulations from various jurisdictions, which govern, among other things, air emissions, wastewater discharges, the handling, storage and disposal of hazardous substances and wastes, the remediation of contaminated sites, post-mining reclamation and restoration of natural resources, and employee health and safety. Future environmental regulations may impose stricter compliance requirements on the industries in which we operate. Additional equipment or process changes at some of our facilities may be needed to meet future requirements. The cost of meeting these requirements may be significant. Failure to comply with such laws and regulations could subject us to administrative, civil or criminal penalties, obligations to pay damages or other costs, and injunctions and other orders, including orders to cease operations.
	We are involved in proceedings under the U.S. Comprehensive Environmental Response, Compensation, and Liability Act, also known as CERCLA or Superfund, or analogous state provisions regarding liability arising from the usage, storage, treatment or disposal of hazardous substances and wastes at a number of sites in the United States, as well as similar proceedings under the laws and regulations of the other jurisdictions in which we have operations, including Brazil and certain countries in the European Union. Many of these jurisdictions have laws that impose joint and several liability, without regard to fault or the legality of the original conduct, for the costs of environmental remediation, natural resource damages, third party claims, and other expenses. In addition, we are, from time to time, subject to environmental reviews and investigations by relevant governmental authorities. We are also involved in claims and litigation filed on behalf of persons alleging exposure to substances and other hazards at our current and former facilities.
	We have established liabilities based on our estimates for the currently anticipated costs associated with these environmental matters. We estimated that the remaining undiscounted clean-up costs related to our environmental liabilities as of June 30, 2014 were approximately $25 million, of which $18 million was associated with a restructuring action and the remaining undiscounted clean-up costs were approximately $7 million. Additionally, $22 million of the environmental liability was included in “Other long-term liabilities,” with the remaining $3 million included in “Accrued expenses and other current liabilities” in our condensed consolidated balance sheet as of June 30, 2014. As of March 31, 2014, $21 million of the environmental liability was included in “Other long-term liabilities,” with the remaining $3 million included in “Accrued expenses and other current liabilities” in our condensed consolidated balance sheet. Management has reviewed the environmental matters, including those for which we assumed liability as a result of our spin-off from Alcan Inc. As a result of this review, management has determined that the currently anticipated costs associated with these environmental matters will not, individually or in the aggregate, materially impact our operations or materially adversely affect our financial condition, results of operations or liquidity.
	Brazil Tax Matters
	Under a federal tax dispute settlement program established by the Brazilian government, we have settled several disputes with Brazil’s tax authorities regarding various forms of manufacturing taxes and social security contributions. In most cases, we are paying the settlement amounts over a period of 180 months, although in some cases we are paying the settlement amounts over a shorter period. The liabilities for these settlements approximate $109 million and $107 million as of June 30, 2014 and March 31, 2014, respectively. As of June 30, 2014, $11 million and $98 million of liabilities were included in “Accrued expenses and other current liabilities” and “Other long-term liabilities,” respectively, in our accompanying condensed consolidated balance sheets. As of March 31, 2014, $11 million and $96 million of liabilities were included in “Accrued expenses and other current liabilities” and “Other long-term liabilities,” respectively. We have recognized net interest expense of $2 million and $1 million for the three months ended June 30, 2014 and 2013, respectively, as which was reported in “Other expense (income), net.”
	As a result of legal proceedings with Brazil’s tax authorities regarding certain tax disputes as of June 30, 2014 and March 31, 2014, we had cash deposits aggregating approximately $7 million and $6 million, respectively, with the Brazilian government. These deposits, which were included in “Other long-term assets — third parties” in our accompanying condensed consolidated balance sheets, will be expended toward these legal proceedings.
	In addition to the disputes we have settled under the federal tax dispute settlement program, we are involved in several other unresolved tax and other legal claims in Brazil. The liabilities recorded for these other disputes and claims were $19 million and $18 million as of June 30, 2014 and March 31, 2014, respectively. Additionally, we have included in the range of reasonably possible losses disclosed above, any unresolved tax disputes or other contingencies for which a loss is reasonably possible and estimable.

Segment_Major_Customer_and_Maj

Segment, Major Customer and Major Supplier Information	3 Months Ended
	Jun. 30, 2014
Segment Reporting [Abstract]	'
SEGMENT, MAJOR CUSTOMER AND MAJOR SUPPLIER INFORMATION	'
	SEGMENT, MAJOR CUSTOMER AND MAJOR SUPPLIER INFORMATION
	Segment Information
	Due in part to the regional nature of supply and demand of aluminum rolled products and to best serve our customers, we manage our activities based on geographical areas and are organized under four operating segments: North America; Europe; Asia and South America. All of our segments manufacture aluminum sheet and light gauge products.
	The following is a description of our operating segments:
	North America. Headquartered in Atlanta, Georgia, this segment operates eight plants, including two fully dedicated recycling facilities and one facility with recycling operations, in two countries.
	Europe. Headquartered in Zurich, Switzerland, this segment operates ten plants, including two fully dedicated recycling facilities and two plants with recycling operations, in four countries.
	Asia. Headquartered in Seoul, South Korea, this segment operates three plants, including two facilities with recycling operations in two countries. Additionally, we have an automotive sheet finishing facility in Changzhou, China that began commissioning in July 2014. We also have a recycling center in Vietnam, which handles the procurement, cleaning and baling of UBCs.
	South America. Headquartered in Sao Paulo, Brazil, this segment comprises smelting operations, power generation, and operates three plants including a facility with recycling operations, in Brazil.
	We measure the profitability and financial performance of our operating segments based on “Segment income.” We define “Segment income” as earnings before (a) “depreciation and amortization”; (b) “interest expense and amortization of debt issuance costs”; (c) “interest income”; (d) unrealized gains (losses) on change in fair value of derivative instruments, net, except for foreign currency remeasurement hedging activities, which are included in segment income; (e) impairment of goodwill; (f) gain or loss on extinguishment of debt; (g) noncontrolling interests' share; (h) adjustments to reconcile our proportional share of “Segment income” from non-consolidated affiliates to income as determined on the equity method of accounting; (i) “restructuring and impairment, net”; (j) gains or losses on disposals of property, plant and equipment and businesses, net; (k) other costs, net; (l) litigation settlement, net of insurance recoveries; (m) sale transaction fees; (n) provision or benefit for taxes on income (loss) and (o) cumulative effect of accounting changes, net of tax.
	The tables below show selected segment financial information (in millions). The “Eliminations and Other” column in the table below includes eliminations and functions that are managed directly from our corporate office that have not been allocated to our operating segments, as well as adjustments for proportional consolidation, and eliminations of intersegment “Net sales.” The financial information for our segments includes the results of our affiliates on a proportionately consolidated basis, which is consistent with the way we manage our business segments. In order to reconcile the financial information for the segments shown in the tables below to the relevant U.S. GAAP-based measures, we must adjust proportional consolidation of each line item. The “Eliminations and Other” in “Net sales – third party” includes the net sales attributable to our joint venture party, Tri-Arrows, for our Logan affiliate because we consolidate 100% of the Logan joint venture for U.S. GAAP, but we manage our Logan affiliate on a proportionately consolidated basis. See Note 5- Consolidation and Note 6 - Investment in and Advances to Non-Consolidated Affiliates and Related Party Transactions for further information about these affiliates. Additionally, we eliminate intersegment sales and intersegment income for reporting on a consolidated basis.
	Selected Segment Financial Information
	June 30, 2014	North				Europe			Asia		South			Other and			Total
		America									America			Eliminations
	Investment in and advances to non–consolidated affiliates	$	—			$	607		$	—	$	—		$	—		$	607
	Assets held for sale - Investment in and advances to non-consolidated affiliates	—				—			—		40			—			40
	Total assets	$	2,805			$	3,165		$	1,562	$	1,714		$	58		$	9,304
	March 31, 2014	North				Europe			Asia		South			Other and			Total
		America									America			Eliminations
	Investment in and advances to non–consolidated affiliates	$	—			$	612		—		$	—		$	—		612
	Assets held for sale - Investment in and advances to non-consolidated affiliates	—				—			—		39			—			39
	Total assets	$	2,998			$	3,046		$	1,440	$	1,583		$	47		$	9,114
	Selected Operating Results Three Months Ended June 30, 2014	North				Europe			Asia		South			Other and			Total
		America									America			Eliminations
	Net sales-third party	$	815			$	880		$	529	$	403		$	53		$	2,680
	Net sales-intersegment	6				34			27		17			(84		)	—
	Net sales	$	821			$	914		$	556	$	420		$	(31	)	$	2,680
	Depreciation and amortization	$	34			$	25		$	20	$	17		$	(7	)	$	89
	Income tax (benefit) provision	$	(9	)		$	12		$	3	$	12		$	6		$	24
	Capital expenditures	$	19			$	89		$	20	$	17		$	(7	)	$	138
	Selected Operating Results Three Months Ended June 30, 2013	North				Europe			Asia		South			Other and			Total
		America									America			Eliminations
	Net sales-third party	$	776			$	778		$	472	$	327		$	48		$	2,401
	Net sales-intersegment	4				29			13		7			(53		)	—
	Net sales	$	780			$	807		$	485	$	334		$	(5	)	$	2,401
	Depreciation and amortization	$	30			$	24		$	14	$	15		$	(6	)	$	77
	Income tax (benefit) provision	$	(1	)		$	11		$	4	$	(15	)	$	4		$	3
	Capital expenditures	$	27			$	36		$	65	$	40		$	13		$	181
	The following table shows the reconciliation from income from reportable segments to “Net income attributable to our common shareholder” (in millions).
		Three Months Ended June 30,
		2014				2013
	North America	$	64			$	46
	Europe	79				70
	Asia	37				46
	South America	55				42
	Depreciation and amortization	(89		)		(77		)
	Interest expense and amortization of debt issuance costs	(81		)		(76		)
	Adjustment to eliminate proportional consolidation	(8		)		(11		)
	Unrealized gains (losses) on change in fair value of derivative instruments, net	1				(12		)
	Realized (losses) gains on derivative instruments not included in segment income	(1		)		2
	Gain on assets held for sale	11				—
	Restructuring and impairment, net	(6		)		(9		)
	Other costs, net	(3		)		(4		)
	Income before income taxes	59				17
	Income tax provision	24				3
	Net income	35				14
	Net income attributable to noncontrolling interests	—				—
	Net income attributable to our common shareholder	$	35			$	14
	Information about Major Customers and Primary Supplier
	The table below shows our net sales to Rexam Plc (Rexam), Affiliates of Ball Corporation and Anheuser-Busch InBev (Anheuser-Busch), our three largest customers, as a percentage of total “Net sales.”
		Three Months Ended June 30,
		2014			2013
	Rexam	18	%		12	%
	Affiliates of Ball Corporation	11	%		10	%
Anheuser-Busch	8	%		8	%
Rio Tinto Alcan (RTA) is our primary supplier of metal inputs, including prime and sheet ingot. The table below shows our purchases from RTA as a percentage of total combined metal purchases.
	Three Months Ended June 30,
	2014			2013
Purchases from RTA as a percentage of total	15	%		18	%

Supplemental_Information

Supplemental Information	3 Months Ended
	Jun. 30, 2014
Supplemental Cash Flow Elements [Abstract]	'
SUPPLEMENTAL INFORMATION	'
	SUPPLEMENTAL INFORMATION
	Supplemental cash flow information (in millions):
		Three Months Ended June 30,
		2014		2013
	Interest paid	$	127	$	124
	Income taxes paid	$	39	$	31
	As of June 30, 2014, we recorded $59 million of outstanding accounts payable and accrued liabilities related to capital expenditures for which the cash outflows will occur subsequent to June 30, 2014.

Supplemental_Guarantor_Informa

Supplemental Guarantor Information	3 Months Ended
	Jun. 30, 2014
Supplemental Guarantor Information [Abstract]	'
SUPPLEMENTAL GUARANTOR INFORMATION	'
	SUPPLEMENTAL GUARANTOR INFORMATION
	In connection with the issuance of Novelis Inc.'s (the Parent and Issuer) 2017 Notes and 2020 Notes, certain of our wholly-owned subsidiaries, which are 100% owned within the meaning of Rule 3-10(h)(1) of Regulation S-X, provided guarantees. These guarantees are full and unconditional as well as joint and several. The guarantor subsidiaries (the Guarantors) are comprised of the majority of our businesses in Canada, the U.S., the U.K., Brazil, Portugal and Switzerland, as well as certain businesses in Germany and France. The remaining subsidiaries (the Non-Guarantors) of the Parent are not guarantors of the Notes.
	CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS
	(in millions)
		Three Months Ended June 30, 2014
		Parent			Guarantors			Non-			Eliminations			Consolidated
								Guarantors
	Net sales	$	174		$	2,235		$	685		$	(414	)	$	2,680
	Cost of goods sold (exclusive of depreciation and amortization)	172			1,950			621			(414		)	2,329
	Selling, general and administrative expenses	(4		)	91			21			—			108
	Depreciation and amortization	4			64			21			—			89
	Research and development expenses	—			12			—			—			12
	Interest expense and amortization of debt issuance costs	80			14			3			(16		)	81
	Gain on assets held for sale	(5		)	(6		)	—			—			(11		)
	Restructuring and impairment, net	—			5			1			—			6
	Equity in net loss of non-consolidated affiliates	—			2			—			—			2
	Equity in net (income) loss of consolidated subsidiaries	(90		)	(9		)	—			99			—
	Other expense (income), net	(20		)	4			5			16			5
		137			2,127			672			(315		)	2,621
	Income (loss) before income taxes	37			108			13			(99		)	59
	Income tax provision	2			18			4			—			24
	Net income (loss)	35			90			9			(99		)	35
	Net income attributable to noncontrolling interests	—			—			—			—			—
	Net income (loss) attributable to our common shareholder	$	35		$	90		$	9		$	(99	)	$	35
	Comprehensive income (loss)	$	66		$	74		$	44		$	(117	)	$	67
	Less: Comprehensive income attributable to noncontrolling interest	$	—		$	—		$	1		$	—		$	1
	Comprehensive income (loss) attributable to our common shareholder	$	66		$	74		$	43		$	(117	)	$	66
	CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS
	(in millions)
		Three Months Ended June 30, 2013
		Parent			Guarantors			Non-			Eliminations			Consolidated
								Guarantors
	Net sales	$	178		$	1,962		$	626		$	(365	)	$	2,401
	Cost of goods sold (exclusive of depreciation and amortization)	189			1,717			557			(365		)	2,098
	Selling, general and administrative expenses	44			63			13			—			120
	Depreciation and amortization	4			58			15			—			77
	Research and development expenses	1			9			—			—			10
	Interest expense and amortization of debt issuance costs	79			7			(1		)	(9		)	76
	Restructuring and impairment, net	—			8			1			—			9
	Equity in net loss of non-consolidated affiliates	—			4			—			—			4
	Equity in net (income) loss of consolidated subsidiaries	(155		)	(26		)	—			181			—
	Other expense (income), net	2			(29		)	8			9			(10		)
		164			1,811			593			(184		)	2,384
	Income (loss) before taxes	14			151			33			(181		)	17
	Income tax (benefit) provision	—			(2		)	5			—			3
	Net income (loss)	14			153			28			(181		)	14
	Net income attributable to noncontrolling interests	—			—			—			—			—
	Net income (loss) attributable to our common shareholder	$	14		$	153		$	28		$	(181	)	$	14
	Comprehensive (loss) income	$	(28	)	$	172		$	6		$	(179	)	$	(29	)
	Comprehensive loss attributable to noncontrolling interest	$	—		$	—		$	(1	)	$	—		$	(1	)
	Comprehensive (loss) income attributable to our common shareholder	$	(28	)	$	172		$	7		$	(179	)	$	(28	)
	CONDENSED CONSOLIDATING BALANCE SHEET (in millions)
		As of June 30, 2014
		Parent			Guarantors			Non-			Eliminations			Consolidated
								Guarantors
	ASSETS
	Current assets
	Cash and cash equivalents	$	4		$	207		$	126		$	—		$	337
	Accounts receivable, net of allowances
	— third parties	21			1,247			289			—			1,557
	— related parties	333			159			88			(519		)	61
	Inventories	43			968			284			—			1,295
	Prepaid expenses and other current assets	7			87			20			—			114
Fair value of derivative instruments	18			19			31			(1		)	67
Deferred income tax assets	—			99			2			—			101
Assets held for sale	—			72			—			—			72
Total current assets	426			2,858			840			(520		)	3,604
Property, plant and equipment, net	98			2,516			961			—			3,575
Goodwill	—			597			11			—			608
Intangible assets, net	18			604			4			—			626
Investments in and advances to non-consolidated affiliates	—			607			—			—			607
Investments in consolidated subsidiaries	3,322			658			—			(3,980		)	—
Deferred income tax assets	—			27			53			—			80
Other long-term assets
— third parties	68			99			16			—			183
— related parties	1,331			70			—			(1,380		)	21
Total assets	$	5,263		$	8,036		$	1,885		$	(5,880	)	$	9,304
LIABILITIES AND EQUITY
Current liabilities
Current portion of long-term debt	$	21		$	10		$	64		$	—		$	95
Short-term borrowings
— third parties	438			443			75			—			956
— related parties	32			88			—			(120		)	—
Accounts payable
— third parties	30			1,066			555			—			1,651
— related parties	55			364			23			(386		)	56
Fair value of derivative instruments	7			46			13			(1		)	65
Accrued expenses and other current liabilities
— third parties	42			331			82			—			455
— related parties	—			9			4			(13		)	—
Deferred income tax liabilities	—			19			—			—			19
Total current liabilities	625			2,376			816			(520		)	3,297
Long-term debt, net of current portion
— third parties	4,215			37			98			—			4,350
— related parties	49			1,272			59			(1,380		)	—
Deferred income tax liabilities	—			415			6			—			421
Accrued postretirement benefits	42			431			159			—			632
Other long-term liabilities	26			234			9			—			269
Total liabilities	4,957			4,765			1,147			(1,900		)	8,969
Commitments and contingencies
Total temporary equity - intercompany	—			1,681			—			(1,681		)	—
Shareholder’s equity
Common stock	—			—			—			—			—
Additional paid-in capital	1,404			—			—			—			1,404
Retained earnings (accumulated deficit)	(1,038		)	1,752			689			(2,441		)	(1,038		)
Accumulated other comprehensive income (loss)	(60		)	(162		)	20			142			(60		)
Total equity of our common shareholder	306			1,590			709			(2,299		)	306
Noncontrolling interests	—			—			29			—			29
Total equity	306			1,590			738			(2,299		)	335
Total liabilities and equity	$	5,263		$	8,036		$	1,885		$	(5,880	)	$	9,304
CONDENSED CONSOLIDATING BALANCE SHEET (in millions)
	As of March 31, 2014
	Parent			Guarantors			Non-			Eliminations			Consolidated
							Guarantors
ASSETS
Current assets
Cash and cash equivalents	$	4		$	372		$	133		$	—		$	509
Accounts receivable, net of allowances
— third parties	15			1,121			246			—			1,382
— related parties	1,093			193			57			(1,289		)	54
Inventories	36			880			257			—			1,173
Prepaid expenses and other current assets	5			76			20			—			101
Fair value of derivative instruments	12			26			14			(1		)	51
Deferred income tax assets	—			96			5			—			101
Assets held for sale	28			74			—			—			102
Total current assets	1,193			2,838			732			(1,290		)	3,473
Property, plant and equipment, net	100			2,485			928			—			3,513
Goodwill	—			600			11			—			611
Intangible assets, net	19			617			4			—			640
Investments in and advances to non-consolidated affiliates	—			612			—			—			612
Investments in consolidated subsidiaries	3,273			612			—			(3,885		)	—
Deferred income tax assets	—			28			52			—			80
Other long-term assets
— third parties	73			89			11			—			173
— related parties	844			61			—			(893		)	12
Total assets	$	5,502		$	7,942		$	1,738		$	(6,068	)	$	9,114
LIABILITIES AND EQUITY
Current liabilities
Current portion of long-term debt	$	21		$	10		$	61		$	—		$	92
Short-term borrowings
— third parties	367			287			69			—			723
— related parties	32			809			—			(841		)	—
Accounts payable
— third parties	35			912			471			—			1,418
— related parties	89			377			29			(442		)	53
Fair value of derivative instruments	14			40			7			(1		)	60
Accrued expenses and other current liabilities
— third parties	104			358			85			—			547
— related parties	250			4			2			(6		)	250
Deferred income tax liabilities	—			16			—			—			16
Liabilities held for sale	10			1			—			—			11
Total current liabilities	922			2,814			724			(1,290		)	3,170
Long-term debt, net of current portion
— third parties	4,219			40			100			—			4,359
— related parties	49			788			56			(893		)	—
Deferred income tax liabilities	—			419			6			—			425
Accrued postretirement benefits	44			422			155			—			621
Other long-term liabilities	28			236			7			—			271
Total liabilities	5,262			4,719			1,048			(2,183		)	8,846
Commitments and contingencies
Total temporary equity - intercompany	—			1,681			—			(1,681		)	—
Shareholder’s equity
Common stock	—			—			—			—			—
Additional paid-in capital	1,404			—			—			—			1,404
Retained earnings (accumulated deficit)	(1,073		)	1,684			680			(2,364		)	(1,073		)
Accumulated other comprehensive income (loss)	(91		)	(142		)	(18		)	160			(91		)
Total equity of our common shareholder	240			1,542			662			(2,204		)	240
Noncontrolling interests	—			—			28			—			28
Total equity	240			1,542			690			(2,204		)	268
Total liabilities and equity	$	5,502		$	7,942		$	1,738		$	(6,068	)	$	9,114
CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS
(in millions)
	Three Months Ended June 30, 2014
	Parent			Guarantors			Non-			Eliminations			Consolidated
							Guarantors
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities	$	(79	)	$	67		$	3		$	(15	)	$	(24	)
INVESTING ACTIVITIES
Capital expenditures	(4		)	(114		)	(20		)	—			(138		)
Proceeds from sales of assets, net of transaction fees
— third parties	29			5			—			—			34
— related parties	—			—			—			—			—
Proceeds (outflows) from investment in and advances to affiliates, net	235			(16		)	—			(235		)	(16		)
Proceeds (outflows) from settlement of other undesignated derivative instruments, net	3			(9		)	7			—			1
Net cash provided by (used in) investing activities	263			(134		)	(13		)	(235		)	(119		)
FINANCING ACTIVITIES
Proceeds from issuance of debt
— third parties	—			95			10			—			105
— related parties	—			500			3			(503		)	—
Principal payments
— third parties	(5		)	(35		)	(13		)	—			(53		)
— related parties	—			(17		)	—			17			—
Short-term borrowings, net
— third parties	71			96			(1		)	—			166
— related parties	—			(721		)	—			721			—
Return of capital to our common shareholder	(250		)	—			—			—			(250		)
Dividends — noncontrolling interests	—			(15		)	—			15			—
Net cash (used in) provided by financing activities	(184		)	(97		)	(1		)	250			(32		)
Net decrease in cash and cash equivalents	—			(164		)	(11		)	—			(175		)
Effect of exchange rate changes on cash	—			(1		)	4			—			3
Cash and cash equivalents — beginning of period	4			372			133			—			509
Cash and cash equivalents — end of period	$	4		$	207		$	126		$	—		$	337
CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS
(in millions)
	Three Months Ended June 30, 2013
	Parent			Guarantors			Non-			Eliminations			Consolidated
							Guarantors
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities	$	(134	)	$	43		$	3		$	(14	)	$	(102	)
INVESTING ACTIVITIES
Capital expenditures	(4		)	(118		)	(59		)	—			(181		)
Net (outflow) proceeds from investment in and advances to affiliates	13			—			—			(13		)	—
Proceeds from settlement of other undesignated derivative instruments, net	2			(13		)	5			—			(6		)
Net cash provided by (used in) investing activities	11			(131		)	(54		)	(13		)	(187		)
FINANCING ACTIVITIES
Proceeds from issuance of debt
— third parties	—			41			1			—			42
— related parties	—			—			21			(21		)	—
Principal payments
— third parties	(5		)	(12		)	—			—			(17		)
Short-term borrowings, net
— third parties	145			74			—			—			219
— related parties	—			(34		)	—			34			—
Dividends, noncontrolling interests	—			(14		)	—			14			—
Debt issuance costs	(7		)	—			—			—			(7		)
Net cash provided by financing activities	133			55			22			27			237
Net increase (decrease) in cash and cash equivalents	10			(33		)	(29		)	—			(52		)
Effect of exchange rate changes on cash	—			1			(1		)	—			—
Cash and cash equivalents — beginning of period	4			196			101			—			301
Cash and cash equivalents — end of period	$	14		$	164		$	71		$	—		$	249

Business_and_Summary_of_Signif1

Business and Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Jun. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Description of Business and Basis of Presentation	'
	We produce aluminum sheet and light gauge products for use in the packaging market, which includes beverage and food can and foil products, as well as for use in the transportation, electronics, architectural and industrial product markets. We also have recycling operations in many of our plants to recycle post-consumer aluminum, such as used-beverage cans (UBCs) and post-industrial aluminum, such as class scrap. As of June 30, 2014, we had manufacturing operations in nine countries on four continents: North America, South America, Asia and Europe; through 24 operating facilities, including recycling operations in ten of these plants. In addition to aluminum rolled products plants, our South American businesses include primary aluminum smelting and power generation facilities.
	The accompanying unaudited condensed consolidated financial statements should be read in conjunction with our audited consolidated financial statements and accompanying notes in our Annual Report on Form 10-K for the year ended March 31, 2014 filed with the United States Securities and Exchange Commission (SEC) on May 16, 2014. Management believes that all adjustments necessary for the fair statement of results, consisting of normally recurring items, have been included in the unaudited condensed consolidated financial statements for the interim periods presented.
	C
Consolidation Policy	'
	Consolidation Policy
	Our condensed consolidated financial statements include the assets, liabilities, revenues and expenses of all wholly-owned subsidiaries and majority-owned subsidiaries over which we exercise control and entities in which we have a controlling financial interest or are deemed to be the primary beneficiary. We eliminate all significant intercompany accounts and transactions from our condensed consolidated financial statements.
	We use the equity method to account for our investments in entities that we do not control, but where we have the ability to exercise significant influence over operating and financial policies. Consolidated “Net income attributable to our common shareholder” includes our share of net income (loss) of these entities. The difference between consolidation and the equity method impacts certain of our financial ratios because of the presentation of the detailed line items reported in the consolidated financial statements for consolidated entities, compared to a two-line presentation of "Investment in and advances to non–consolidated affiliates" and "Equity in net loss of non-consolidated affiliates."
Use of Estimates, Policy [Policy Text Block]	'
	Use of Estimates and Assumptions
	The preparation of our condensed consolidated financial statements in conformity with accounting principles generally accepted in the United States of America (GAAP) requires us to make estimates and assumptions. These estimates and assumptions affect the reported amounts of assets and liabilities and the disclosures of contingent assets and liabilities as of the date of the financial statements, and the reported amounts of revenues and expenses during the reporting periods. The principal areas of judgment relate to (1) the fair value of derivative financial instruments; (2) impairment of goodwill; (3) impairment of long lived assets and other intangible assets; (4) impairment of and assessment of consolidation of equity investments; (5) actuarial assumptions related to pension and other postretirement benefit plans; (6) tax uncertainties and valuation allowances; and (7) assessment of loss contingencies, including environmental and litigation liabilities. Future events and their effects cannot be predicted with certainty, and accordingly, our accounting estimates require the exercise of judgment. The accounting estimates used in the preparation of our condensed consolidated financial statements will change as new events occur, as more experience is acquired, as additional information is obtained and as our operating environment changes. We evaluate and update our assumptions and estimates on an ongoing basis and may employ outside experts to assist in our evaluations. Actual results could differ from our estimates.
New Accounting Pronouncements, Policy [Policy Text Block]	'
	Recently Adopted Accounting Standards
	Effective for the first quarter of fiscal 2015, we adopted Financial Accounting Standards Board ASU No. 2013-11, Income Taxes (Topic 740): Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. The amendments in this update provide guidance on the presentation of unrecognized tax benefits and will better reflect the manner in which an entity would settle, at the reporting date, any additional income taxes that would result from the disallowance of a tax position when net operating loss carryforwards, similar tax losses, or tax credit carryforwards exist. The adoption of this standard had an insignificant impact on our consolidated financial position.
Description of New Accounting Pronouncements Not yet Adopted [Text Block]	'
	Recently Issued Accounting Standards
	In March 2013, the FASB issued ASU No. 2013-05, Foreign Currency Matters (Topic 830): Parent's Accounting for the Cumulative Translation Adjustment upon Derecognition of Certain Subsidiaries or Groups of Assets within a Foreign Entity or of an Investment in a Foreign Entity. The amendments in this update provide clarification regarding the release of a cumulative translation adjustment into net income when a parent either sells a part or all of its investment in a foreign entity or no longer holds a controlling financial interest in a subsidiary or group of assets within a foreign entity. The guidance will be effective for annual reporting periods beginning after December 15, 2014, and interim periods within those annual periods. We will adopt this standard prospectively in our first quarter ending June 30, 2015 and our current accounting policies comply with this guidance. Therefore, this will not have a material impact to our historical financial statements.
	In April 2014, the FASB issued ASU No. 2014-08, Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity. The amendments in this update change the criteria for determining which disposals can be presented as discontinued operations and modify related disclosure requirements. Under the revised standard, a discontinued operation is (1) a component of an entity or group of components that has been disposed of by sale, disposed of other than by sale or is classified as held for sale that represents a strategic shift that has or will have a major effect on an entity’s operations and financial results or (2) an acquired business or nonprofit activity that is classified as held for sale on the date of the acquisition. The guidance is effective for annual periods beginning on or after December 15, 2014 and interim periods within that year. The guidance will be applied prospectively. Early adoption is permitted but only for disposals (or classifications as held for sale) that have not been reported in financial statements previously issued or available for issue. We will adopt this standard prospectively in our first quarter ending June 30, 2015 on future disposals. The accounting treatment and classification of future disposals under this new standard could differ from our current treatment and classification of disposals in our current consolidated financial statements.
	In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (ASC 606), which, when effective, will supersede the guidance in former ASC 605, Revenue Recognition. The new guidance requires entities to recognize revenue based on the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance is effective for annual periods beginning on or after December 31, 2016 and interim periods within that year. Early adoption is not permitted. We will adopt this standard in our first quarter ending June 30, 2017. We are currently evaluating the impact of this standard on our consolidated financial position and results of operations.

Restructuring_and_Impairment_T

Restructuring and Impairment (Tables)	3 Months Ended
	Jun. 30, 2014
Restructuring and Related Activities [Abstract]	'
Schedule of restructuring liability activity and other impairment charges	'
	The following table summarizes our restructuring liability activity and other impairment charges (in millions).
			Total restructuring			Other restructuring charges				Total restructuring charges			Other impairments (B)		Total
			liabilities			(A)									restructuring
															and impairments, net
	Balance as of March 31, 2014		$	47
	Expenses		6			$	—			$	6		$	—	$	6
	Cash payments		(7		)
	Balance as of June 30, 2014		$	46
	(A)	Other restructuring charges include period expenses that were not recorded through the restructuring liability and impairments related to a restructuring activity.
	(B)	Other impairment charges not related to a restructuring activity.
North America [Member]	'
Restructuring Cost and Reserve [Line Items]	'
Summary of restructuring reserve activity	'
	The following table summarizes our restructuring activity for the North America segment by plan (in millions).
				Three Months Ended June 30,			Year Ended March 31,				Prior to April 1,
				2014			2014				2013
	Restructuring charges - North America
	Saguenay Plant Closure:
		Severance		$	—		$	—			$	5
		Fixed asset impairment (A)		—			—				28
		Other exit related costs		—			1				—
		Period expenses (A)		—			1				3
	Relocation of R&D operations to Kennesaw, Georgia
		Severance		—			1				11
		Relocation costs		—			1				—
		Period expenses (A)		—			1				—
	Total restructuring charges - North America			$	—		$	5			$	47
	Restructuring payments - North America
		Severance		$	—		$	(4	)
		Other		—			(2		)
	Total restructuring payments - North America			$	—		$	(6	)
	(A)     These charges were not recorded through the restructuring liability.
Europe [Member]	'
Restructuring Cost and Reserve [Line Items]	'
Summary of restructuring reserve activity	'
	The following table summarizes our restructuring activity for the Europe segment by plan (in millions).
			Three Months Ended June 30,			Year Ended March 31,				Prior to April 1,
			2014			2014				2013
	Restructuring charges - Europe
	Business optimization
		Severance	$	3		$	26			$	16
		Pension settlement loss (A)	—			1				—
	Total restructuring charges - Europe		$	3		$	27			$	16
	Total restructuring payments - Europe
		Severance	$	(6	)	$	(18	)
		Other	—			(1		)
	Total restructuring payments - Europe		$	(6	)	$	(19	)
	(A)     These charges were not recorded through the restructuring liability.
South America [Member]	'
Restructuring Cost and Reserve [Line Items]	'
Summary of restructuring reserve activity	'
	The following table summarizes our restructuring activity for the South America segment by plan (in millions).
			Three Months Ended June 30,			Year Ended March 31,				Prior to April 1,
			2014			2014				2013
	Restructuring charges - South America
	Non-core assets
		Severance	$	—		$	2			$	3
		Asset impairments (A)	—			—				1
		Contract termination and other	—			1				5
		Environmental charges	2			16				—
	Aratu plant closure
		Severance				—				7
		Asset impairments (A)	—			—				7
		Other exit costs	1			—				6
	Total restructuring charges - South America		$	3		$	19			$	29
	Restructuring payments - South America
		Severance	$	—		$	(4	)
		Other	(1		)	(4		)
	Total restructuring payments - South America		$	(1	)	$	(8	)
	(A)     These charges were not recorded through the restructuring liability.
Corporate [Member]	'
Restructuring Cost and Reserve [Line Items]	'
Summary of restructuring reserve activity	'
	The following table summarizes our restructuring activity for the Corporate operations by plan (in millions).
			Three Months Ended June 30,			Year Ended March 31,				Prior to April 1,
			2014			2014				2013
	Restructuring charges - Corporate
	Relocation costs of global headquarters		$	—		$	—			$	5
	Restructuring payments - Corporate
		Lease Termination Costs	$	—		$	(1	)
	Total restructuring payments - Corporate		$	—		$	(1	)

Inventories_Tables

Inventories (Tables)	3 Months Ended
	Jun. 30, 2014
Inventory Disclosure [Abstract]	'
Schedule of inventories	'
	Inventories" consist of the following (in millions).
		June 30,		March 31,
		2014		2014
	Finished goods	$	325	$	259
	Work in process	480		419
	Raw materials	372		382
	Supplies	118		113
	Inventories	$	1,295	$	1,173

Assets_Held_For_Sale_Assets_He

Assets Held For Sale Assets Held For Sale (Tables)	3 Months Ended
	Jun. 30, 2014
Assets Held For Sale [Abstract]	'
Schedule of assets held-for-sale	'
	The following table summarizes the carrying amounts of the major classes of assets and liabilities held for sale (in millions).
		June 30,		March 31,
		2014		2014
	Assets held for sale
	Accounts receivable	$	—	$	10
	Inventories	—		15
	Prepaid expenses and other current assets	—		1
	Property, plant and equipment, net	32		37
	Investment in and advances to non-consolidated affiliates	40		39
	Total assets held for sale	$	72	$	102
	Liabilities held for sale
	Accounts payable	$	—	$	4
	Accrued expenses and other current liabilities	—		7
	Total liabilities held for sale	$	—	$	11

Consolidation_Tables

Consolidation (Tables) (Logan [Member])	3 Months Ended
	Jun. 30, 2014
Logan [Member]	'
Variable Interest Entity [Line Items]	'
Schedule of variable interest entity	'
		June 30,		March 31,
		2014		2014
	Assets
	Current assets
	Cash and cash equivalents	$	—	$	1
	Accounts receivable	39		38
	Inventories	45		42
	Prepaid expenses and other current assets	1		1
	Total current assets	85		82
	Property, plant and equipment, net	11		14
	Goodwill	12		12
	Deferred income taxes	65		63
	Other long-term assets	2		3
	Total assets	$	175	$	174
	Liabilities
	Current liabilities
	Accounts payable	$	25	$	26
	Accrued expenses and other current liabilities	13		13
	Total current liabilities	38		39
	Accrued postretirement benefits	144		141
	Other long-term liabilities	2		2
	Total liabilities	$	184	$	182

Investment_In_and_Advances_To_1

Investment In and Advances To Non-Consolidated Affiliates and Related Party Transactions (Tables)	3 Months Ended
	Jun. 30, 2014
Related Party Transactions [Abstract]	'
Summary of condensed results of operations of equity method affiliates	'
		Three Months Ended June 30,
		2014			2013
	Net sales	$	138		$	131
	Costs and expenses related to net sales	146			127
	(Benefit) provision for taxes on income	(2		)	4
	Net loss	$	(6	)	$	—
	Purchase of tolling services from Aluminium Norf GmbH (Norf)	$	69		$	66
Period-end account balances with non-consolidated affiliates, shown as related party balances	'
		June 30,			March 31,
		2014			2014
	Accounts receivable-related parties	$	61		$	54
	Other long-term assets-related parties	$	21		$	12
	Accounts payable-related parties	$	56		$	53

Debt_Tables

Debt (Tables)	3 Months Ended
	Jun. 30, 2014
Debt Disclosure [Abstract]	'
Schedule of debt	'
	Debt consisted of the following (in millions).
		June 30, 2014												March 31, 2014
		Interest		Principal			Unamortized				Carrying			Principal			Unamortized				Carrying
		Rates (A)					Carrying  Value				Value						Carrying  Value				Value
							Adjustments										Adjustments
	Third party debt:
	Short term borrowings	3.58	%	$	956		$	—			$	956		$	723		$	—			$	723
	Novelis Inc.
	Floating rate Term Loan Facility, due March 2017	3.75	%	1,745			(19		)	(B)	1,726			1,749			(20		)	(B)	1,729
	8.375% Senior Notes, due December 2017	8.375	%	1,100			—				1,100			1,100			—				1,100
	8.75% Senior Notes, due December 2020	8.75	%	1,400			—				1,400			1,400			—				1,400
	Capital lease obligations, due through July 2017	3.64	%	10			—				10			11			—				11
	Novelis Korea Limited
	Loans, due December 2014 through December 2015 (KRW 162 billion)	3.58	%	160			—				160			155			—				155
	Novelis Switzerland S.A.
	Capital lease obligation, due through December 2019 (Swiss francs (CHF) 31 million)	7.5	%	35			(1		)	(C)	34			36			(1		)	(C)	35
	Novelis do Brasil Ltda.
	BNDES loans, due February 2015 through April 2021 (BRL 27 million)	6.29	%	12			(2		)	(D)	10			13			(2		)	(D)	11
	Other
	Other debt, due through December 2020	5.74	%	5			—				5			10			—				10
	Total debt			5,423			(22		)		5,401			5,197			(23		)		5,174
	Less: Short-term borrowings			(956		)	—				(956		)	(723		)	—				(723		)
	Current portion of long term debt			(95		)	—				(95		)	(92		)	—				(92		)
	Long-term debt, net of current portion			$	4,372		$	(22	)		$	4,350		$	4,382		$	(23	)		$	4,359
	(A)	Interest rates are the fixed or variable rates as specified in the debt instruments (not the effective interest rate) as of June 30, 2014, and therefore, exclude the effects of related interest rate swaps, accretion/amortization of fair value adjustments as a result of purchase accounting in connection with Hindalco's purchase of Novelis and accretion/amortization of debt issuance costs related to the debt exchange completed in fiscal 2009 and the series of refinancing transactions and additional borrowings we completed in fiscal 2011, 2012 and 2013. We present stated rates of interest because they reflect the rate at which cash will be paid for future debt service.
	(B)	Debt existing at the time of Hindalco's purchase of Novelis was recorded at fair value. In connection with a series of refinancing transactions, a portion of the historical fair value adjustments were allocated to the Term Loan Facility, resulting in carrying value adjustments on this debt obligation. The unamortized carrying value also includes an issuance discount.
	(C)	Debt existing at the time of Hindalco's purchase of Novelis was recorded at fair value resulting in carrying value adjustments to our capital lease obligations in Novelis Switzerland.
	(D)	The unamortized carrying value includes issuance discounts related to the difference resulting from the contractual rates of interest specified in the instruments that are lower than the market rates of interest upon issuance.
Principal repayment requirements for total debt over the next five years and thereafter	'
	Principal repayment requirements for our total debt over the next five years and thereafter (excluding unamortized carrying value adjustments and using exchange rates as of June 30, 2014 for our debt denominated in foreign currencies) are as follows (in millions).
	As of June 30, 2014	Amount
	Short-term borrowings and current portion of long-term debt due within one year	$	1,051
	2 years	126
	3 years	1,720
	4 years	1,109
	5 years	9
	Thereafter	1,408
	Total	$	5,423

ShareBased_Compensation_Tables

Share-Based Compensation (Tables)	3 Months Ended
	Jun. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Total compensation expense related to SARs and RSUs under the long term incentive plans	'
		Three Months Ended June 30,
		2014			2013
	Total compensation expense	$	4		$	13
Hindalco and Novelis SARs activity and RSUs	'
	The table below shows the RSUs activity for the three months ended June 30, 2014.
			Number of		Grant Date Fair		Aggregate
			RSUs		Value		Intrinsic
					(in Indian Rupees)		Value (USD
							in millions)
	RSUs outstanding as of March 31, 2014		4,490,860		120.42		$	11
	Granted		1,455,206		145.5		—
	Exercised		(682,361	)	191.98		—
	Forfeited/Cancelled		(80,833	)	143.19		—
	RSUs outstanding as of June 30, 2014		5,182,872		118.47		$	15
	The table below shows the Hindalco SARs activity for the three months ended June 30, 2014.
			Number of		Weighted		Weighted Average		Aggregate
			SARs		Average		Remaining		Intrinsic
					Exercise Price		Contractual Term		Value (USD
					(in Indian Rupees)		(in years)		in millions)
	SARs outstanding as of March 31, 2014		21,635,392		112.26		4.3		$	13
	Granted		4,868,698		145.5		7		—
	Exercised		(4,128,272	)	89.97		—		—
	Forfeited/Cancelled		(730,823	)	131.29		—		—
	SARs outstanding as of June 30, 2014		21,644,995		123.35		4.9		$	17
	SARs exercisable as of June 30, 2014		8,339,534		121.52		3.3		$	8
	The table below shows the Novelis SARs activity for the three months ended June 30, 2014.
			Number of		Weighted			Weighted Average		Aggregate
			SARs		Average			Remaining		Intrinsic
					Exercise Price			Contractual Term		Value (USD
					(in USD)			(In years)		in millions)
	SARs outstanding as of March 31, 2014		668,402		$	90.09		5.3		$	2
	Granted		376,173		94.4			7		—
	Exercised		(12,244	)	66.46			—		—
	Forfeited/Cancelled		(33,760	)	83.77			—		—
	SARs outstanding as of June 30, 2014		998,571		$	92.22		5.8		$	4
	SARs exercisable as of June 30, 2014		223,623		$	89		4.8		$	2
Assumptions used in estimating fair value of each SAR under 2013 LTIP, 2012 LTIP, 2011 LTIP, 2010 LTIP, 2009 LTIP	'
	The fair value of each unvested Hindalco SAR was estimated using the following assumptions:
			Three Months Ended June 30,
			2014		2013
	Risk-free interest rate		8.56% - 8.78%		7.63% - 7.75%
	Dividend yield		0.61	%	1.4	%
	Volatility		43% - 55%		39% - 52%
	The fair value of each unvested Novelis SAR was estimated using the following assumptions:
			Three Months Ended June 30,
			2014		2013
	Risk-free interest rate		1.21% - 2.10%		1.00% - 1.66%
	Dividend yield		—	%	—	%
	Volatility		30% - 43%		31% - 41%

Postretirement_Benefit_Plans_T

Postretirement Benefit Plans (Tables)	3 Months Ended
	Jun. 30, 2014
Compensation and Retirement Disclosure [Abstract]	'
Components of net periodic benefit cost for all significant postretirement benefit plans	'
	Components of net periodic benefit cost for all of our significant postretirement benefit plans are shown in the tables below (in millions).
		Pension Benefit Plans						Other Benefit Plans
		Three Months Ended June 30,						Three Months Ended June 30,
		2014			2013			2014			2013
	Service cost	$	11		$	13		$	1		$	3
	Interest cost	17			16			1			2
	Expected return on assets	(17		)	(16		)	—			—
	Amortization — losses, net	6			5			2			1
	Amortization — prior service credit, net	(1		)	—			(10		)	—
	Termination benefits / curtailments	1			—			(2		)	—
	Net periodic benefit cost	$	17		$	18		$	(8	)	$	6
Contributions to employee benefit plans	'
	We contributed the following amounts to all plans (in millions).
		Three Months Ended June 30,
		2014			2013
	Funded pension plans	$	4		$	6
	Unfunded pension plans	1			2
	Savings and defined contribution pension plans	6			5
	Total contributions	$	11		$	13

Currency_Gains_Losses_Tables

Currency (Gains) Losses (Tables)	3 Months Ended
	Jun. 30, 2014
Foreign Currency [Abstract]	'
Currency (gains) losses included in "Other (income) expense, net"	'
	The following currency (gains) losses are included in “Other expense (income), net” in the accompanying condensed consolidated statements of operations (in millions).
		Three Months Ended June 30,
		2014			2013
	Loss (gain) on remeasurement of monetary assets and liabilities, net	$	11		$	(18	)
	Loss released from accumulated other comprehensive income	—			1
	(Gain) loss recognized on balance sheet remeasurement currency exchange contracts, net	(11		)	12
	Currency gains, net	$	—		$	(5	)
Currency gains (losses) included in "AOCI," net of tax and "Noncontrolling interests"	'
	The following currency gains (losses) are included in Accumulated other comprehensive loss (“AOCI”), net of tax and “Noncontrolling interests” in the accompanying condensed consolidated balance sheets (in millions).
		Three Months Ended June 30, 2014			Year Ended
					31-Mar-14
	Cumulative currency translation adjustment — beginning of period	$	90		$	(30	)
	Effect of changes in exchange rates	27			120
	Cumulative currency translation adjustment — end of period	$	117		$	90

Financial_Instruments_and_Comm1

Financial Instruments and Commodity Contracts (Tables)	3 Months Ended
	Jun. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Fair values of financial instruments and commodity contracts	'
	The gross fair values of our financial instruments and commodity contracts as of June 30, 2014 and March 31, 2014 are as follows (in millions):
		June 30, 2014
		Assets							Liabilities						Net Fair Value
		Current				Noncurrent (A)			Current			Noncurrent (A)			Assets/(Liabilities)
	Derivatives designated as hedging instruments:
	Cash flow hedges
	Aluminum contracts	$	—			$	—		$	(13	)	$	—		$	(13	)
	Currency exchange contracts	23				9			(7		)	(4		)	21
	Energy contracts	2				—			—			—			2
	Interest rate swaps	—				—			(1		)	—			(1		)
	Total derivatives designated as hedging instruments	$	25			$	9		$	(21	)	$	(4	)	$	9
	Derivatives not designated as hedging instruments
	Aluminum contracts	16				—			(29		)	—			(13		)
	Currency exchange contracts	26				—			(9		)	—			17
	Energy contracts	—				—			(6		)	(11		)	(17		)
	Total derivatives not designated as hedging instruments	42				—			(44		)	(11		)	(13		)
	Total derivative fair value	$	67			$	9		$	(65	)	$	(15	)	$	(4	)
		March 31, 2014
		Assets							Liabilities						Net Fair Value
		Current				Noncurrent (A)			Current			Noncurrent(A)			Assets/(Liabilities)
	Derivatives designated as hedging instruments:
	Cash flow hedges
	Aluminum contracts	$	4			$	—		$	(7	)	$	—		$	(3	)
	Currency exchange contracts	15				4			(13		)	(6		)	—
	Energy contracts	3				—			—			—			3
	Net investment hedges
	Currency exchange contracts	—				—			(1		)	—			(1		)
	Fair value hedges
	Aluminum contracts	—				—			(1		)	—			(1		)
	Total derivatives designated as hedging instruments	$	22			$	4		$	(22	)	$	(6	)	$	(2	)
	Derivatives not designated as hedging instruments:
	Aluminum contracts	19				—			(28		)	—			(9		)
	Currency exchange contracts	9				—			(3		)	—			6
	Energy contracts	1				—			(7		)	(13		)	(19		)
	Total derivatives not designated as hedging instruments	29				—			(38		)	(13		)	(22		)
	Total derivative fair value	$	51			$	4		$	(60	)	$	(19	)	$	(24	)
	(A)	The noncurrent portions of derivative assets and liabilities are included in “Other long-term assets-third parties” and in “Other long-term liabilities” respectively, in the accompanying condensed consolidated balance sheets.
Summary of notional amount	'
	The following table summarizes our notional amount (in kt).
		June 30,			March 31,
		2014			2014
	Hedge Type
	Purchase (Sale)
	Cash flow purchases	3			16
	Cash flow sales	(262	)		(222	)
	Fair value	5			9
	Not designated	(89	)		(105	)
	Total, net	(343	)		(302	)
Summary of gains (losses) associated with the change in the fair value derivative instruments recognized in "Other (income) expense, net"	'
	The following table summarizes the gains (losses) associated with the change in fair value of derivative instruments not designated as hedges and the ineffectiveness of designated derivatives recognized in “Other (income) expense, net” (in millions). Gains (losses) recognized in other line items in the condensed consolidated statement of operations are separately disclosed within this footnote.
		Three Months Ended June 30,
		2014				2013
	Derivative instruments not designated as hedges
	Aluminum contracts	$	(7	)		$	(2	)
	Currency exchange contracts	12				(12		)
	Energy contracts (A)	2				—
	Gain (loss) recognized in "Other expense (income), net"	$	7			$	(14	)
	Derivative instruments designated as hedges
	Gain recognized in "Other expense (income), net" (B)	2				10
	Total gain (loss) recognized in "Other expense (income), net"	$	9			$	(4	)
	Balance sheet remeasurement currency exchange contracts	$	11			$	(13	)
	Realized (losses) gains, net	(3		)		21
	Unrealized gains (losses) on other derivative instruments, net	1				(12		)
	Total gain (loss) recognized in "Other expense (income), net"	$	9			$	(4	)
	(A)	Includes amounts related to de-designated electricity swap.
	(B)	Amount includes: forward market premium/discount excluded and hedging relationship ineffectiveness on designated aluminum and foreign currency capex contracts; releases to income from AOCI on balance sheet remeasurement contracts; and ineffectiveness on fair value hedges involving aluminum derivatives.
Summary of the impact on AOCI and earnings of derivative instruments designated as cash flow hedges	'
	The following table summarizes the impact on AOCI and earnings of derivative instruments designated as cash flow and net investment hedges (in millions). Within the next twelve months, we expect to reclassify $2 million of gains from AOCI to earnings, before taxes.
		Amount of Gain (Loss)							Amount of Gain (Loss)
		Recognized in OCI							Recognized in “Other (Income)
		(Effective Portion)							Expense, net” (Ineffective and
									Excluded Portion)
		Three Months Ended June 30,							Three Months Ended June 30,
		2014				2013			2014			2013
	Cash flow hedging derivatives
	Aluminum contracts	$	(21	)		$	29		$	3		$	11
	Currency exchange contracts	32				(51		)	(1		)	—
	Energy contracts (A)	—				(2		)	—			—
	Total	$	11			$	(24	)	$	2		$	11
	Gain (Loss) Reclassification
		Amount of Gain (Loss) Reclassified from AOCI into Income/(Expense) three months ended June 30,							Location of Gain (Loss)
									Reclassified from AOCI into
									Earnings
	Cash flow hedging derivatives	2014				2013
	Energy contracts (A)	$	(1	)		$	(1	)	Other expense (income), net
	Energy contracts (C)	1				—			Cost of goods sold (B)
	Aluminum contracts	(6		)		21			Cost of goods sold (B)
	Aluminum contracts	—				2			Net sales
	Currency exchange contracts	1				1			Cost of goods sold (B)
	Currency exchange contracts	4				—			Net sales
	Currency exchange contracts	1				(1		)	Other expense (income), net
	Total	$	—			$	22		Income before taxes
		—				(7		)	Income tax provision
		$	—			$	15		Net income
	(A)	Includes amounts related to de-designated electricity swap. AOCI related to this swap is amortized to income over the remaining term of the hedged item.
	(B)	"Cost of goods sold" is exclusive of depreciation and amortization.
	(C)	Includes amounts related to natural gas swaps.

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Loss) (Tables)	3 Months Ended
	Jun. 30, 2014
Equity [Abstract]	'
Accumulated other comprehensive income, net of tax	'
	The following tables summarize the change in the components of accumulated other comprehensive income (loss) net of tax, for the periods presented (in millions).
			Currency Translation				(A) Cash Flow Hedges				(B)			Total
											Postretirement Benefit Plans
	Balance as of March 31, 2014		$	89			$	(20	)		$	(160	)	$	(91	)
	Other comprehensive income before reclassifications		26				13				(5		)	34
	Amounts reclassified from AOCI, net		—				—				(3		)	(3		)
	Net current-period other comprehensive income (loss)		26				13				(8		)	31
	Balance as of June 30, 2014		$	115			$	(7	)		$	(168	)	$	(60	)
			Currency Translation				(A) Cash Flow Hedges				(B)			Total
											Postretirement Benefit Plans
	Balance as of March 31, 2013		$	(33	)		$	(2	)		$	(233	)	$	(268	)
	Other comprehensive income before reclassifications		(2		)		(29		)		—			(31		)
	Amounts reclassified from AOCI, net		—				(15		)		4			(11		)
	Net current-period other comprehensive income (loss)		(2		)		(44		)		4			(42		)
	Balance as of June 30, 2013		$	(35	)		$	(46	)		$	(229	)	$	(310	)
	(A)  For additional information on our cash flow hedges see Note 11 - Financial Instruments and Commodity Contracts.
	(B)	For additional information on our postretirement benefit plans see Note 9 - Postretirement Benefit Plans.
	The following table summarizes the impact on AOCI and earnings of derivative instruments designation as cash flow hedges (in millions).
		Amount of Gain (Loss) Reclassified from AOCI into Income/(Expense) three months ended June 30,								Location of Gain (Loss)
										Reclassified from AOCI into
										Earnings
	Cash flow hedging derivatives	2014				2013
	Energy contracts (A)	$	(1	)		$	(1	)		Other expense (income), net
	Energy contracts (C)	1				—				Cost of goods sold (B)
	Aluminum contracts	(6		)		21				Cost of goods sold (B)
	Aluminum contracts	—				2				Net sales
	Currency exchange contracts	1				1				Cost of goods sold (B)
	Currency exchange contracts	4				—				Net sales
	Currency exchange contracts	1				(1		)		Other expense (income), net
	Total	$	—			$	22			Income before taxes
		—				(7		)		Income tax provision
		$	—			$	15			Net income
	(A)	Includes amounts related to de-designated electricity swap. AOCI related to this swap is amortized to income over the remaining term of the hedged item.
	(B)	"Cost of goods sold" is exclusive of depreciation and amortization.
	(C)	Includes amounts related to natural gas swaps.

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Jun. 30, 2014
Fair Value Disclosures [Abstract]	'
Derivative assets and liabilities measured and recognized at fair value on a recurring basis classified under the appropriate level of the fair value hierarchy	'
	The following tables present our derivative assets and liabilities which were measured and recognized at fair value on a recurring basis classified under the appropriate level of the fair value hierarchy as of June 30, 2014 and March 31, 2014 (in millions).
		June 30, 2014						March 31, 2014
		Assets			Liabilities			Assets			Liabilities
	Level 2 instruments
	Aluminum contracts	$	16		$	(42	)	$	23		$	(36	)
	Currency exchange contracts	58			(20		)	28			(23		)
	Energy contracts	2			—			4			(1		)
	Interest rate swaps	—			(1		)	—			—
	Total level 2 instruments	76			(63		)	55			(60		)
	Level 3 instruments
	Energy contracts	—			(17		)	—			(19		)
	Total level 3 instruments	—			(17		)	—			(19		)
	Total gross	$	76		$	(80	)	$	55		$	(79	)
	Netting adjustment (A)	(21		)	21			(20		)	20
	Total net	$	55		$	(59	)	$	35		$	(59	)
Reconciliation of fair value activity for Level 3 derivative contracts	'
	The following table presents a reconciliation of fair value activity for Level 3 derivative contracts (in millions).
		Level 3  –
		Derivative Instruments (A)
	Balance as of March 31, 2014	$	(19	)
	Realized/unrealized gain included in earnings (B)	4
	Settlements	(2		)
	Balance as of June 30, 2014	$	(17	)
	(A)    Represents net derivative liabilities.
	(B)    Included in “Other expense (income), net.”
Estimated fair value of certain financial instruments that are not recorded at fair value on a recurring basis	'
		June 30, 2014						March 31, 2014
		Carrying			Fair			Carrying			Fair
		Value			Value			Value			Value
	Assets
	Long-term receivables from related parties	$	21		$	21		$	12		$	12
	Liabilities
	Total debt — third parties (excluding short term borrowings)	$	4,445		$	4,655		$	4,451		$	4,734

Other_Income_Expense_Net_Table

Other (Income) Expense, Net (Tables)	3 Months Ended
	Jun. 30, 2014
Other Income and Expenses [Abstract]	'
Schedule of other nonoperating income (expense)	'
		Three Months Ended June 30,
		2014			2013
	Foreign currency remeasurement gains, net (A)	$	—		$	(5	)
	(Gain) loss on change in fair value of other unrealized derivative instruments, net	(1		)	12
	Loss (gain) on change in fair value of other realized derivative instruments, net	3			(21		)
	Loss on Brazilian tax litigation, net (B)	2			1
	Interest income	(1		)	(1		)
	Other, net	2			4
	Other expense (income), net	$	5		$	(10	)
	(A)	Includes “(Gain) loss recognized on balance sheet remeasurement currency exchange contracts, net.”
	(B)	See Note 16 – Commitments and Contingencies – Brazil Tax and Legal Matters for further details.

Income_Taxes_Tables

Income Taxes (Tables)	3 Months Ended
	Jun. 30, 2014
Income Tax Disclosure [Abstract]	'
Reconciliation of Canadian statutory tax rates to effective tax rates	'
	A reconciliation of the Canadian statutory tax rate to our effective tax rate was as follows (in millions, except percentages).
		Three Months Ended June 30,
		2014			2013
	Pre-tax income before equity in net income of non-consolidated affiliates and noncontrolling interests	$	61		$	21
	Canadian statutory tax rate	25		%	26		%
	Provision at the Canadian statutory rate	$	15		$	5
	Increase (decrease) for taxes on income (loss) resulting from:
	Exchange translation items	4			(9		)
	Exchange remeasurement of deferred income taxes	4			(15		)
	Change in valuation allowances	11			37
	Income items not subject to tax	(1		)	(1		)
	Dividends not subject to tax	(10		)	(14		)
	Tax rate differences on foreign earnings	1			—
	Income tax provision	$	24		$	3
	Effective tax rate	39		%	14		%

Segment_Major_Customer_and_Maj1

Segment, Major Customer and Major Supplier Information (Tables)	3 Months Ended
	Jun. 30, 2014
Segment Reporting [Abstract]	'
Selected segment financial information	'
	Selected Segment Financial Information
	June 30, 2014	North				Europe			Asia		South			Other and			Total
		America									America			Eliminations
	Investment in and advances to non–consolidated affiliates	$	—			$	607		$	—	$	—		$	—		$	607
	Assets held for sale - Investment in and advances to non-consolidated affiliates	—				—			—		40			—			40
	Total assets	$	2,805			$	3,165		$	1,562	$	1,714		$	58		$	9,304
	March 31, 2014	North				Europe			Asia		South			Other and			Total
		America									America			Eliminations
	Investment in and advances to non–consolidated affiliates	$	—			$	612		—		$	—		$	—		612
	Assets held for sale - Investment in and advances to non-consolidated affiliates	—				—			—		39			—			39
	Total assets	$	2,998			$	3,046		$	1,440	$	1,583		$	47		$	9,114
	Selected Operating Results Three Months Ended June 30, 2014	North				Europe			Asia		South			Other and			Total
		America									America			Eliminations
	Net sales-third party	$	815			$	880		$	529	$	403		$	53		$	2,680
	Net sales-intersegment	6				34			27		17			(84		)	—
	Net sales	$	821			$	914		$	556	$	420		$	(31	)	$	2,680
	Depreciation and amortization	$	34			$	25		$	20	$	17		$	(7	)	$	89
	Income tax (benefit) provision	$	(9	)		$	12		$	3	$	12		$	6		$	24
	Capital expenditures	$	19			$	89		$	20	$	17		$	(7	)	$	138
	Selected Operating Results Three Months Ended June 30, 2013	North				Europe			Asia		South			Other and			Total
		America									America			Eliminations
	Net sales-third party	$	776			$	778		$	472	$	327		$	48		$	2,401
	Net sales-intersegment	4				29			13		7			(53		)	—
	Net sales	$	780			$	807		$	485	$	334		$	(5	)	$	2,401
	Depreciation and amortization	$	30			$	24		$	14	$	15		$	(6	)	$	77
	Income tax (benefit) provision	$	(1	)		$	11		$	4	$	(15	)	$	4		$	3
	Capital expenditures	$	27			$	36		$	65	$	40		$	13		$	181
Reconciliation from income from reportable segments to "Net income attributable to out common shareholder"	'
	The following table shows the reconciliation from income from reportable segments to “Net income attributable to our common shareholder” (in millions).
		Three Months Ended June 30,
		2014				2013
	North America	$	64			$	46
	Europe	79				70
	Asia	37				46
	South America	55				42
	Depreciation and amortization	(89		)		(77		)
	Interest expense and amortization of debt issuance costs	(81		)		(76		)
	Adjustment to eliminate proportional consolidation	(8		)		(11		)
	Unrealized gains (losses) on change in fair value of derivative instruments, net	1				(12		)
	Realized (losses) gains on derivative instruments not included in segment income	(1		)		2
	Gain on assets held for sale	11				—
	Restructuring and impairment, net	(6		)		(9		)
	Other costs, net	(3		)		(4		)
	Income before income taxes	59				17
	Income tax provision	24				3
	Net income	35				14
	Net income attributable to noncontrolling interests	—				—
	Net income attributable to our common shareholder	$	35			$	14
Net sales to largest customers, as a percentage of total Net sales	'
	The table below shows our net sales to Rexam Plc (Rexam), Affiliates of Ball Corporation and Anheuser-Busch InBev (Anheuser-Busch), our three largest customers, as a percentage of total “Net sales.”
		Three Months Ended June 30,
		2014			2013
	Rexam	18	%		12	%
	Affiliates of Ball Corporation	11	%		10	%
	Anheuser-Busch	8	%		8	%
Percentage of total combined metal purchases	'
	The table below shows our purchases from RTA as a percentage of total combined metal purchases.
		Three Months Ended June 30,
		2014			2013
	Purchases from RTA as a percentage of total	15	%		18	%

Supplemental_Information_Table

Supplemental Information (Tables)	3 Months Ended
	Jun. 30, 2014
Supplemental Cash Flow Elements [Abstract]	'
Accumulated other comprehensive income, net of tax	'
	The following tables summarize the change in the components of accumulated other comprehensive income (loss) net of tax, for the periods presented (in millions).
			Currency Translation				(A) Cash Flow Hedges				(B)			Total
											Postretirement Benefit Plans
	Balance as of March 31, 2014		$	89			$	(20	)		$	(160	)	$	(91	)
	Other comprehensive income before reclassifications		26				13				(5		)	34
	Amounts reclassified from AOCI, net		—				—				(3		)	(3		)
	Net current-period other comprehensive income (loss)		26				13				(8		)	31
	Balance as of June 30, 2014		$	115			$	(7	)		$	(168	)	$	(60	)
			Currency Translation				(A) Cash Flow Hedges				(B)			Total
											Postretirement Benefit Plans
	Balance as of March 31, 2013		$	(33	)		$	(2	)		$	(233	)	$	(268	)
	Other comprehensive income before reclassifications		(2		)		(29		)		—			(31		)
	Amounts reclassified from AOCI, net		—				(15		)		4			(11		)
	Net current-period other comprehensive income (loss)		(2		)		(44		)		4			(42		)
	Balance as of June 30, 2013		$	(35	)		$	(46	)		$	(229	)	$	(310	)
	(A)  For additional information on our cash flow hedges see Note 11 - Financial Instruments and Commodity Contracts.
	(B)	For additional information on our postretirement benefit plans see Note 9 - Postretirement Benefit Plans.
	The following table summarizes the impact on AOCI and earnings of derivative instruments designation as cash flow hedges (in millions).
		Amount of Gain (Loss) Reclassified from AOCI into Income/(Expense) three months ended June 30,								Location of Gain (Loss)
										Reclassified from AOCI into
										Earnings
	Cash flow hedging derivatives	2014				2013
	Energy contracts (A)	$	(1	)		$	(1	)		Other expense (income), net
	Energy contracts (C)	1				—				Cost of goods sold (B)
	Aluminum contracts	(6		)		21				Cost of goods sold (B)
	Aluminum contracts	—				2				Net sales
	Currency exchange contracts	1				1				Cost of goods sold (B)
	Currency exchange contracts	4				—				Net sales
	Currency exchange contracts	1				(1		)		Other expense (income), net
	Total	$	—			$	22			Income before taxes
		—				(7		)		Income tax provision
		$	—			$	15			Net income
	(A)	Includes amounts related to de-designated electricity swap. AOCI related to this swap is amortized to income over the remaining term of the hedged item.
	(B)	"Cost of goods sold" is exclusive of depreciation and amortization.
	(C)	Includes amounts related to natural gas swaps.
Supplemental cash flow information	'
	Supplemental cash flow information (in millions):
		Three Months Ended June 30,
		2014				2013
	Interest paid	$	127			$	124
	Income taxes paid	$	39			$	31

Supplemental_Guarantor_Informa1

Supplemental Guarantor Information (Tables)	3 Months Ended
	Jun. 30, 2014
Supplemental Guarantor Information [Abstract]	'
Condensed consolidating statement of operations	'
	CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS
	(in millions)
		Three Months Ended June 30, 2014
		Parent			Guarantors			Non-			Eliminations			Consolidated
								Guarantors
	Net sales	$	174		$	2,235		$	685		$	(414	)	$	2,680
	Cost of goods sold (exclusive of depreciation and amortization)	172			1,950			621			(414		)	2,329
	Selling, general and administrative expenses	(4		)	91			21			—			108
	Depreciation and amortization	4			64			21			—			89
	Research and development expenses	—			12			—			—			12
	Interest expense and amortization of debt issuance costs	80			14			3			(16		)	81
	Gain on assets held for sale	(5		)	(6		)	—			—			(11		)
	Restructuring and impairment, net	—			5			1			—			6
	Equity in net loss of non-consolidated affiliates	—			2			—			—			2
	Equity in net (income) loss of consolidated subsidiaries	(90		)	(9		)	—			99			—
	Other expense (income), net	(20		)	4			5			16			5
		137			2,127			672			(315		)	2,621
	Income (loss) before income taxes	37			108			13			(99		)	59
	Income tax provision	2			18			4			—			24
	Net income (loss)	35			90			9			(99		)	35
	Net income attributable to noncontrolling interests	—			—			—			—			—
	Net income (loss) attributable to our common shareholder	$	35		$	90		$	9		$	(99	)	$	35
	Comprehensive income (loss)	$	66		$	74		$	44		$	(117	)	$	67
	Less: Comprehensive income attributable to noncontrolling interest	$	—		$	—		$	1		$	—		$	1
	Comprehensive income (loss) attributable to our common shareholder	$	66		$	74		$	43		$	(117	)	$	66
	CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS
	(in millions)
		Three Months Ended June 30, 2013
		Parent			Guarantors			Non-			Eliminations			Consolidated
								Guarantors
	Net sales	$	178		$	1,962		$	626		$	(365	)	$	2,401
	Cost of goods sold (exclusive of depreciation and amortization)	189			1,717			557			(365		)	2,098
	Selling, general and administrative expenses	44			63			13			—			120
	Depreciation and amortization	4			58			15			—			77
	Research and development expenses	1			9			—			—			10
	Interest expense and amortization of debt issuance costs	79			7			(1		)	(9		)	76
	Restructuring and impairment, net	—			8			1			—			9
	Equity in net loss of non-consolidated affiliates	—			4			—			—			4
	Equity in net (income) loss of consolidated subsidiaries	(155		)	(26		)	—			181			—
	Other expense (income), net	2			(29		)	8			9			(10		)
		164			1,811			593			(184		)	2,384
	Income (loss) before taxes	14			151			33			(181		)	17
	Income tax (benefit) provision	—			(2		)	5			—			3
	Net income (loss)	14			153			28			(181		)	14
	Net income attributable to noncontrolling interests	—			—			—			—			—
	Net income (loss) attributable to our common shareholder	$	14		$	153		$	28		$	(181	)	$	14
	Comprehensive (loss) income	$	(28	)	$	172		$	6		$	(179	)	$	(29	)
	Comprehensive loss attributable to noncontrolling interest	$	—		$	—		$	(1	)	$	—		$	(1	)
	Comprehensive (loss) income attributable to our common shareholder	$	(28	)	$	172		$	7		$	(179	)	$	(28	)
Condensed consolidating balance sheet	'
	CONDENSED CONSOLIDATING BALANCE SHEET (in millions)
		As of June 30, 2014
		Parent			Guarantors			Non-			Eliminations			Consolidated
								Guarantors
	ASSETS
	Current assets
	Cash and cash equivalents	$	4		$	207		$	126		$	—		$	337
	Accounts receivable, net of allowances
	— third parties	21			1,247			289			—			1,557
	— related parties	333			159			88			(519		)	61
	Inventories	43			968			284			—			1,295
	Prepaid expenses and other current assets	7			87			20			—			114
	Fair value of derivative instruments	18			19			31			(1		)	67
	Deferred income tax assets	—			99			2			—			101
	Assets held for sale	—			72			—			—			72
	Total current assets	426			2,858			840			(520		)	3,604
	Property, plant and equipment, net	98			2,516			961			—			3,575
	Goodwill	—			597			11			—			608
	Intangible assets, net	18			604			4			—			626
	Investments in and advances to non-consolidated affiliates	—			607			—			—			607
	Investments in consolidated subsidiaries	3,322			658			—			(3,980		)	—
	Deferred income tax assets	—			27			53			—			80
	Other long-term assets
	— third parties	68			99			16			—			183
	— related parties	1,331			70			—			(1,380		)	21
	Total assets	$	5,263		$	8,036		$	1,885		$	(5,880	)	$	9,304
	LIABILITIES AND EQUITY
	Current liabilities
	Current portion of long-term debt	$	21		$	10		$	64		$	—		$	95
	Short-term borrowings
	— third parties	438			443			75			—			956
	— related parties	32			88			—			(120		)	—
	Accounts payable
	— third parties	30			1,066			555			—			1,651
	— related parties	55			364			23			(386		)	56
	Fair value of derivative instruments	7			46			13			(1		)	65
	Accrued expenses and other current liabilities
	— third parties	42			331			82			—			455
	— related parties	—			9			4			(13		)	—
	Deferred income tax liabilities	—			19			—			—			19
	Total current liabilities	625			2,376			816			(520		)	3,297
	Long-term debt, net of current portion
	— third parties	4,215			37			98			—			4,350
	— related parties	49			1,272			59			(1,380		)	—
	Deferred income tax liabilities	—			415			6			—			421
	Accrued postretirement benefits	42			431			159			—			632
	Other long-term liabilities	26			234			9			—			269
	Total liabilities	4,957			4,765			1,147			(1,900		)	8,969
	Commitments and contingencies
	Total temporary equity - intercompany	—			1,681			—			(1,681		)	—
	Shareholder’s equity
	Common stock	—			—			—			—			—
	Additional paid-in capital	1,404			—			—			—			1,404
	Retained earnings (accumulated deficit)	(1,038		)	1,752			689			(2,441		)	(1,038		)
	Accumulated other comprehensive income (loss)	(60		)	(162		)	20			142			(60		)
	Total equity of our common shareholder	306			1,590			709			(2,299		)	306
	Noncontrolling interests	—			—			29			—			29
	Total equity	306			1,590			738			(2,299		)	335
	Total liabilities and equity	$	5,263		$	8,036		$	1,885		$	(5,880	)	$	9,304
	CONDENSED CONSOLIDATING BALANCE SHEET (in millions)
		As of March 31, 2014
		Parent			Guarantors			Non-			Eliminations			Consolidated
								Guarantors
ASSETS
Current assets
Cash and cash equivalents	$	4		$	372		$	133		$	—		$	509
Accounts receivable, net of allowances
— third parties	15			1,121			246			—			1,382
— related parties	1,093			193			57			(1,289		)	54
Inventories	36			880			257			—			1,173
Prepaid expenses and other current assets	5			76			20			—			101
Fair value of derivative instruments	12			26			14			(1		)	51
Deferred income tax assets	—			96			5			—			101
Assets held for sale	28			74			—			—			102
Total current assets	1,193			2,838			732			(1,290		)	3,473
Property, plant and equipment, net	100			2,485			928			—			3,513
Goodwill	—			600			11			—			611
Intangible assets, net	19			617			4			—			640
Investments in and advances to non-consolidated affiliates	—			612			—			—			612
Investments in consolidated subsidiaries	3,273			612			—			(3,885		)	—
Deferred income tax assets	—			28			52			—			80
Other long-term assets
— third parties	73			89			11			—			173
— related parties	844			61			—			(893		)	12
Total assets	$	5,502		$	7,942		$	1,738		$	(6,068	)	$	9,114
LIABILITIES AND EQUITY
Current liabilities
Current portion of long-term debt	$	21		$	10		$	61		$	—		$	92
Short-term borrowings
— third parties	367			287			69			—			723
— related parties	32			809			—			(841		)	—
Accounts payable
— third parties	35			912			471			—			1,418
— related parties	89			377			29			(442		)	53
Fair value of derivative instruments	14			40			7			(1		)	60
Accrued expenses and other current liabilities
— third parties	104			358			85			—			547
— related parties	250			4			2			(6		)	250
Deferred income tax liabilities	—			16			—			—			16
Liabilities held for sale	10			1			—			—			11
Total current liabilities	922			2,814			724			(1,290		)	3,170
Long-term debt, net of current portion
— third parties	4,219			40			100			—			4,359
— related parties	49			788			56			(893		)	—
Deferred income tax liabilities	—			419			6			—			425
Accrued postretirement benefits	44			422			155			—			621
Other long-term liabilities	28			236			7			—			271
Total liabilities	5,262			4,719			1,048			(2,183		)	8,846
Commitments and contingencies
Total temporary equity - intercompany	—			1,681			—			(1,681		)	—
Shareholder’s equity
Common stock	—			—			—			—			—
Additional paid-in capital	1,404			—			—			—			1,404
Retained earnings (accumulated deficit)	(1,073		)	1,684			680			(2,364		)	(1,073		)
Accumulated other comprehensive income (loss)	(91		)	(142		)	(18		)	160			(91		)
Total equity of our common shareholder	240			1,542			662			(2,204		)	240
Noncontrolling interests	—			—			28			—			28
Total equity	240			1,542			690			(2,204		)	268
Total liabilities and equity	$	5,502		$	7,942		$	1,738		$	(6,068	)	$	9,114
Condensed consolidating statement of cash flows	'
	CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS
	(in millions)
		Three Months Ended June 30, 2014
		Parent			Guarantors			Non-			Eliminations			Consolidated
								Guarantors
	OPERATING ACTIVITIES
	Net cash (used in) provided by operating activities	$	(79	)	$	67		$	3		$	(15	)	$	(24	)
	INVESTING ACTIVITIES
	Capital expenditures	(4		)	(114		)	(20		)	—			(138		)
	Proceeds from sales of assets, net of transaction fees
	— third parties	29			5			—			—			34
	— related parties	—			—			—			—			—
	Proceeds (outflows) from investment in and advances to affiliates, net	235			(16		)	—			(235		)	(16		)
	Proceeds (outflows) from settlement of other undesignated derivative instruments, net	3			(9		)	7			—			1
	Net cash provided by (used in) investing activities	263			(134		)	(13		)	(235		)	(119		)
	FINANCING ACTIVITIES
	Proceeds from issuance of debt
	— third parties	—			95			10			—			105
	— related parties	—			500			3			(503		)	—
	Principal payments
	— third parties	(5		)	(35		)	(13		)	—			(53		)
	— related parties	—			(17		)	—			17			—
	Short-term borrowings, net
	— third parties	71			96			(1		)	—			166
	— related parties	—			(721		)	—			721			—
	Return of capital to our common shareholder	(250		)	—			—			—			(250		)
	Dividends — noncontrolling interests	—			(15		)	—			15			—
	Net cash (used in) provided by financing activities	(184		)	(97		)	(1		)	250			(32		)
	Net decrease in cash and cash equivalents	—			(164		)	(11		)	—			(175		)
	Effect of exchange rate changes on cash	—			(1		)	4			—			3
	Cash and cash equivalents — beginning of period	4			372			133			—			509
	Cash and cash equivalents — end of period	$	4		$	207		$	126		$	—		$	337
	CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS
	(in millions)
		Three Months Ended June 30, 2013
		Parent			Guarantors			Non-			Eliminations			Consolidated
								Guarantors
	OPERATING ACTIVITIES
	Net cash (used in) provided by operating activities	$	(134	)	$	43		$	3		$	(14	)	$	(102	)
	INVESTING ACTIVITIES
	Capital expenditures	(4		)	(118		)	(59		)	—			(181		)
	Net (outflow) proceeds from investment in and advances to affiliates	13			—			—			(13		)	—
	Proceeds from settlement of other undesignated derivative instruments, net	2			(13		)	5			—			(6		)
	Net cash provided by (used in) investing activities	11			(131		)	(54		)	(13		)	(187		)
	FINANCING ACTIVITIES
	Proceeds from issuance of debt
	— third parties	—			41			1			—			42
	— related parties	—			—			21			(21		)	—
	Principal payments
	— third parties	(5		)	(12		)	—			—			(17		)
	Short-term borrowings, net
	— third parties	145			74			—			—			219
	— related parties	—			(34		)	—			34			—
	Dividends, noncontrolling interests	—			(14		)	—			14			—
	Debt issuance costs	(7		)	—			—			—			(7		)
	Net cash provided by financing activities	133			55			22			27			237
	Net increase (decrease) in cash and cash equivalents	10			(33		)	(29		)	—			(52		)
	Effect of exchange rate changes on cash	—			1			(1		)	—			—
	Cash and cash equivalents — beginning of period	4			196			101			—			301
	Cash and cash equivalents — end of period	$	14		$	164		$	71		$	—		$	249

Business_and_Summary_of_Signif2

Business and Summary of Significant Accounting Policies (Details)	Jun. 30, 2014
	Plants
	Continents
	Countries
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Number of countries Company operates in	9
Numer of continents Company operates in	4
Number of operating plants	24
Number of plants with recycling operations	10

Restructuring_and_Impairment_R

Restructuring and Impairment - Restructuring Liability (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013
Total restructuring liabilities	'		'
Balance, beginning of period	$47		'
Expenses	6		'
Cash payments	-7		'
Balance, end of period	46		'
Other restructuring charges	0	[1]	'
Total restructuring charges	6		'
Other impairments	0	[2]	'
Total restructuring and impairments, net	$6		$9
[1]	Other restructuring charges include period expenses that were not recorded through the restructuring liability and impairments related to a restructuring activity.
[2]	Other impairment charges not related to a restructuring activity.

Restructuring_and_Impairment_D

Restructuring and Impairment (Details) (USD $)	3 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014		Mar. 31, 2014		Mar. 31, 2013
Restructuring Cost and Reserve [Line Items]	'		'		'
Restructuring charges	$6		'		'
Cash payments	-7		'		'
North America [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Restructuring charges	0		5		47
Cash payments	0		-6		'
North America [Member] | Severance [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Cash payments	0		-4		'
North America [Member] | Severance [Member] | Saguenay Plant Closure [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Restructuring charges	0		0		5
North America [Member] | Severance [Member] | Relocation of Research and Development Operations [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Restructuring charges	0		1		11
North America [Member] | Fixed Asset Impairment [Member] | Saguenay Plant Closure [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Restructuring charges	0	[1]	0	[1]	28	[1]
North America [Member] | Other Exit Related Costs [Member] | Saguenay Plant Closure [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Restructuring charges	0		1		0
North America [Member] | Period Expenses [Member] | Saguenay Plant Closure [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Restructuring charges	0	[1]	1	[1]	3	[1]
North America [Member] | Period Expenses [Member] | Relocation of Research and Development Operations [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Restructuring charges	0	[1]	1	[1]	0	[1]
North America [Member] | Relocation Costs [Member] | Relocation of Research and Development Operations [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Restructuring charges	0		1		0
North America [Member] | Other [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Cash payments	0		-2		'
Europe [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Restructuring charges	3		27		16
Cash payments	-6		-19		'
Europe [Member] | Severance [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Cash payments	-6		-18		'
Europe [Member] | Severance [Member] | Business Optimization [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Restructuring charges	3		26		16
Europe [Member] | Other [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Cash payments	0		-1		'
Europe [Member] | Pension Settlement Loss [Member] | Business Optimization [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Restructuring charges	0	[1]	1	[1]	0	[1]
South America [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Restructuring charges	3		19		29
Cash payments	-1		-8		'
South America [Member] | Severance [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Cash payments	0		-4		'
South America [Member] | Severance [Member] | Non-core Assets [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Restructuring charges	0		2		3
South America [Member] | Severance [Member] | Aratu Plant Closure [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Restructuring charges	'		0		7
South America [Member] | Fixed Asset Impairment [Member] | Non-core Assets [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Restructuring charges	0	[1]	0	[1]	1	[1]
South America [Member] | Fixed Asset Impairment [Member] | Aratu Plant Closure [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Restructuring charges	0	[1]	0	[1]	7	[1]
South America [Member] | Other Exit Related Costs [Member] | Aratu Plant Closure [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Restructuring charges	1		0		6
South America [Member] | Other [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Cash payments	-1		-4		'
South America [Member] | Contract Termination and Other [Member] | Non-core Assets [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Restructuring charges	0		1		5
South America [Member] | Environmental Charges [Member] | Non-core Assets [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Restructuring charges	2		16		0
Corporate [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Cash payments	0		-1		'
Corporate [Member] | Relocation of Headquarters [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Restructuring charges	0		0		5
Corporate [Member] | Other [Member]	'		'		'
Restructuring Cost and Reserve [Line Items]	'		'		'
Cash payments	$0		($1)		'
[1]	These charges were not recorded through the restructuring liability.

Restructuring_and_Impairment_D1

Restructuring and Impairment (Details Textual) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Mar. 31, 2014
Restructuring Cost and Reserve [Line Items]	'	'	'
Restructuring and impairment, net	$6	$9	'
Restructuring liability	46	'	47
Accrued expenses and other current liabilities [Member]	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'
Restructuring liabilities, short-term	27	'	'
Other long-term liabilities [Member]	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'
Restructuring liabilities, long-term	19	'	'
North America [Member]	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'
Restructuring liability	4	'	'
North America [Member] | Severance [Member]	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'
Restructuring liability	3	'	'
North America [Member] | Other Exit Related Costs [Member]	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'
Restructuring liability	1	'	'
Europe [Member]	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'
Restructuring liability	15	'	'
Europe [Member] | Severance [Member]	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'
Restructuring liability	14	'	'
Europe [Member] | Environmental Remediation and Other Restructuring [Member]	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'
Restructuring liability	1	'	'
South America [Member] | Other Exit Related Costs [Member] | Non-core Assets [Member]	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'
Restructuring liability	6	'	'
South America [Member] | Environmental, Contract Termination and Other Exit Related Costs [Member]	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'
Restructuring liability	26	'	'
South America [Member] | Environmental Remediation Site [Domain] | Non-core Assets [Member]	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'
Restructuring liability	19	'	'
South America [Member] | Contract Termination [Member] | Non-core Assets [Member]	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'
Restructuring liability	1	'	'
Corporate [Member] | Relocation of Headquarters [Member]	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'
Restructuring liability	$1	'	'

Inventories_Details

Inventories (Details) (USD $)	Jun. 30, 2014	Mar. 31, 2014
In Millions, unless otherwise specified
Schedule of inventories	'	'
Finished goods	$325	$259
Work in process	480	419
Raw materials	372	382
Supplies	118	113
Inventories	$1,295	$1,173

Assets_Held_For_Sale_Assets_He1

Assets Held For Sale Assets Held For Sale (Details) (USD $)	Jun. 30, 2014	Mar. 31, 2014
In Millions, unless otherwise specified
Assets Held For Sale [Abstract]	'	'
Accounts receivable	$0	$10
Inventories	0	15
Prepaid expenses and other current assets	0	1
Property, plant and equipment, net	32	37
Investment in and advances to non-consolidated affiliates	40	39
Total assets held for sale	72	102
Accounts payable	0	4
Accrued expenses and other current liabilities	0	7
Total liabilities held for sale	$0	$11

Assets_Held_For_Sale_Assets_He2

Assets Held For Sale Assets Held For Sale (Details Textual) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Mar. 31, 2014
Assets Held-for-sale [Line Items]	'	'	'
Assets held for sale	$72	'	$102
Liabilities of Assets Held-for-sale	0	'	11
Loss (gain) on assets held for sale	11	0	'
Gain (Loss) on Disposition of Property Plant Equipment	-1	-1	'
South America [Member]	'	'	'
Assets Held-for-sale [Line Items]	'	'	'
Assets held for sale	72	'	'
Brazil [Member]	'	'	'
Assets Held-for-sale [Line Items]	'	'	'
Loss (gain) on assets held for sale	4	'	'
Proceeds from Sale of Property Held-for-sale	4	'	'
North America [Member]	'	'	'
Assets Held-for-sale [Line Items]	'	'	'
Loss (gain) on assets held for sale	7	'	'
Proceeds from Sale of Property Held-for-sale	31	'	'
Accounts Receivable [Member] | North America [Member]	'	'	'
Assets Held-for-sale [Line Items]	'	'	'
Proceeds from Sale of Property Held-for-sale	$1	'	'

Consolidation_Details

Consolidation (Details) (USD $)	Jun. 30, 2014	Mar. 31, 2014	Jun. 30, 2013	Mar. 31, 2013
In Millions, unless otherwise specified
Current assets	'	'	'	'
Cash and cash equivalents	$337	$509	$249	$301
Inventories	1,295	1,173	'	'
Prepaid expenses and other current assets	114	101	'	'
Total current assets	3,604	3,473	'	'
Property, plant and equipment, net	3,575	3,513	'	'
Goodwill	608	611	'	'
Deferred income taxes	80	80	'	'
Other long-term assets	183	173	'	'
Total assets	9,304	9,114	'	'
Current liabilities	'	'	'	'
Accounts payable	1,651	1,418	'	'
Accrued expenses and other current liabilities	455	547	'	'
Total current liabilities	3,297	3,170	'	'
Accrued postretirement benefits	632	621	'	'
Other long-term liabilities	269	271	'	'
Total liabilities	8,969	8,846	'	'
Logan [Member]	'	'	'	'
Current assets	'	'	'	'
Cash and cash equivalents	0	1	'	'
Accounts receivable - third parties	39	38	'	'
Inventories	45	42	'	'
Prepaid expenses and other current assets	1	1	'	'
Total current assets	85	82	'	'
Property, plant and equipment, net	11	14	'	'
Goodwill	12	12	'	'
Deferred income taxes	65	63	'	'
Other long-term assets	2	3	'	'
Total assets	175	174	'	'
Current liabilities	'	'	'	'
Accounts payable	25	26	'	'
Accrued expenses and other current liabilities	13	13	'	'
Total current liabilities	38	39	'	'
Accrued postretirement benefits	144	141	'	'
Other long-term liabilities	2	2	'	'
Total liabilities	$184	$182	'	'

Investment_In_and_Advances_To_2

Investment In and Advances To Non-Consolidated Affiliates and Related Party Transactions (Details) (Equity method investments [Member], USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Equity method investments [Member]	'	'
Summary of the share of the condensed results of operations of equity method affiliates	'	'
Net sales	$138	$131
Costs, expenses and provisions for taxes on income	146	127
Equity Method Investment, Summarized Financial Information, Provision For Income Tax	-2	4
Net loss	-6	0
Purchase of tolling services from Aluminum Norf GmbH (Norf)	$69	$66

Investment_In_and_Advances_To_3

Investment In and Advances To Non-Consolidated Affiliates and Related Party Transactions (Details1) (USD $)	Jun. 30, 2014	Mar. 31, 2014
In Millions, unless otherwise specified
Related Party Transaction [Line Items]	'	'
Accounts receivable - related parties	$61	$54
Long-term receivables from related parties, carrying value	21	12
Accounts payable	56	53
Alunorf [Member]	'	'
Related Party Transaction [Line Items]	'	'
Accounts receivable - related parties	'	54
Long-term receivables from related parties, carrying value	'	12
Accounts payable	'	$53

Investment_In_and_Advances_To_4

Investment In and Advances To Non-Consolidated Affiliates and Related Party Transactions (Details Textual)	3 Months Ended			3 Months Ended				3 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Mar. 31, 2014	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Mar. 31, 2014	Jun. 30, 2014	Jun. 30, 2014	Jun. 30, 2014	Jun. 30, 2014
	USD ($)	USD ($)	USD ($)	Alunorf [Member]	Alunorf [Member]	Alunorf [Member]	Alunorf [Member]	Hindalco [Member]	AV Metals, Inc. [Member]	Supplemental Employee Retirement Plan, Defined Benefit [Member]	Supplemental Employee Retirement Plan, Defined Benefit [Member]
				USD ($)	USD ($)	EUR (€)	USD ($)	USD ($)	USD ($)	Alunorf [Member]	Alunorf [Member]
										USD ($)	EUR (€)
Schedule of Equity Method Investments [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Related Party Transactions Interest Income On Loan	'	'	'	$1,000,000	'	'	'	'	'	'	'
Proceeds from Related Party Debt	0	0	'	'	'	'	'	'	'	'	'
Related Party Transactions Interest Income On Loan Description	'	'	'	'less than $1 million	'less than $1 million	'	'	'	'	'	'
Related Party Transactions Sales between Company and Parent	'	'	'	1	1	'	'	'	'	'	'
Investment In and Advances To Non-Consolidated Affiliates and Related Party Transactions [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Equity in net loss of non-consolidated affiliates	-2,000,000	-4,000,000	'	'	'	'	'	'	'	'	'
Long-term receivables from related parties, carrying value	21,000,000	'	12,000,000	'	'	'	12,000,000	'	'	'	'
Accounts receivable - related parties	61,000,000	'	54,000,000	'	'	'	54,000,000	0	'	'	'
Guarantee as percentage of outstanding debt	'	'	'	50.00%	'	'	'	'	'	'	'
Maximum exposure for gauranteed obligation	'	'	'	'	'	6,000,000	'	'	'	4,000,000	3,000,000
Revenue from related party	'	'	'	'	'	'	'	1,000,000	'	'	'
Return of Capital to Parent Company	'	'	'	'	'	'	'	'	$250,000,000	'	'

Debt_Details

Debt (Details) (USD $)	Jun. 30, 2014		Mar. 31, 2014
In Millions, unless otherwise specified
Debt Instrument [Line Items]	'		'
Long-term debt, Carrying Value	$4,445		$4,451
Total debt	5,423		5,197
Total debt, Unamortized Carrying Value Adjustment	-22		-23
Total debt, carrying value	5,401		5,174
Short-term borrowings	-956		-723
Current portion of long-term debt	-95		-92
Long-term debt, net of current portion, Principal	4,372		4,382
Long-term debt, net of current portion, Carrying Value	4,350		4,359
Floating Rate Term Loan Facility, due March 2017 [Member]	'		'
Debt Instrument [Line Items]	'		'
Interest Rates	3.75%	[1]	'
Long-term debt, Principal	1,745		1,749
Long-term debt, Unamortized Carrying Value Adjustments	-19	[2]	-20	[2]
Long-term debt, Carrying Value	1,726		1,729
8.375% Senior Notes, due December 2017 [Member]	'		'
Debt Instrument [Line Items]	'		'
Interest Rates	8.38%	[1]	'
Long-term debt, Principal	1,100		1,100
Long-term debt, Unamortized Carrying Value Adjustments	0		0
Long-term debt, Carrying Value	1,100		1,100
8.75% Senior Notes, due December 2020 [Member]	'		'
Debt Instrument [Line Items]	'		'
Interest Rates	8.75%	[1]	'
Long-term debt, Principal	1,400		1,400
Long-term debt, Unamortized Carrying Value Adjustments	0		0
Long-term debt, Carrying Value	1,400		1,400
Capital Lease Obligation due July 2017 [Member]	'		'
Debt Instrument [Line Items]	'		'
Interest Rates	3.64%	[1]	'
Long-term debt, Principal	10		11
Long-term debt, Unamortized Carrying Value Adjustments	0		0
Long-term debt, Carrying Value	10		11
Korean Loans due December 2014 through 2015 [Member] | Korea [Member]	'		'
Debt Instrument [Line Items]	'		'
Interest Rates	3.58%	[1]	'
Long-term debt, Principal	160		155
Long-term debt, Unamortized Carrying Value Adjustments	0		0
Long-term debt, Carrying Value	160		155
Capital Lease Obligation, due December 2019 [Member] | Switzerland [Member]	'		'
Debt Instrument [Line Items]	'		'
Interest Rates	7.50%	[1]	'
Capital lease obligation, Principal	35		36
Capital lease obligation, Unamortized Carrying Value Adjustments	-1	[3]	-1	[3]
Capital lease obligation, Carrying Value	34		35
BNDES Loans, due March 2015 through April 2021 [Member] | Brazil [Member]	'		'
Debt Instrument [Line Items]	'		'
Interest Rates	6.29%	[1]	'
Long-term debt, Principal	12		13
Long-term debt, Unamortized Carrying Value Adjustments	-2	[4]	-2	[4]
Long-term debt, Carrying Value	10		11
Other Debt, due through December 2020 [Member]	'		'
Debt Instrument [Line Items]	'		'
Interest Rates	5.74%	[1]	'
Long-term debt, Principal	5		10
Long-term debt, Unamortized Carrying Value Adjustments	0		0
Long-term debt, Carrying Value	5		10
Short term borrowings [Member]	'		'
Debt Instrument [Line Items]	'		'
Interest Rates	3.58%	[1]	'
Short-term borrowings	($956)		($723)
[1]	Interest rates are the fixed or variable rates as specified in the debt instruments (not the effective interest rate) as of June 30, 2014, and therefore, exclude the effects of related interest rate swaps, accretion/amortization of fair value adjustments as a result of purchase accounting in connection with Hindalco's purchase of Novelis and accretion/amortization of debt issuance costs related to the debt exchange completed in fiscal 2009 and the series of refinancing transactions and additional borrowings we completed in fiscal 2011, 2012 and 2013. We present stated rates of interest because they reflect the rate at which cash will be paid for future debt service.
[2]	Debt existing at the time of Hindalco's purchase of Novelis was recorded at fair value. In connection with a series of refinancing transactions, a portion of the historical fair value adjustments were allocated to the Term Loan Facility, resulting in carrying value adjustments on this debt obligation. The unamortized carrying value also includes an issuance discount.
[3]	Debt existing at the time of Hindalco's purchase of Novelis was recorded at fair value resulting in carrying value adjustments to our capital lease obligations in Novelis Switzerland.
[4]	The unamortized carrying value includes issuance discounts related to the difference resulting from the contractual rates of interest specified in the instruments that are lower than the market rates of interest upon issuance.

Debt_Principal_Repayments_Deta

Debt (Principal Repayments) (Details) (USD $)	Jun. 30, 2014	Mar. 31, 2014
In Millions, unless otherwise specified
Maturities of long-term debt outstanding	'	'
Short-term borrowings and current portion of long term debt due within one year	$1,051	'
2 years	126	'
3 years	1,720	'
4 years	1,109	'
5 years	9	'
Thereafter	1,408	'
Total debt	$5,423	$5,197

Debt_Senior_Secured_Credit_Fac

Debt (Senior Secured Credit Facilities) (Details)

3 Months Ended

0 Months Ended

0 Months Ended

3 Months Ended

Jun. 30, 2014

13-May-13

13-May-13

13-May-13

13-May-13

13-May-13

13-May-13

13-May-13

13-May-13

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

ABL Facility [Member]

ABL Revolver [Member]

ABL Revolver [Member]

ABL Revolver [Member]

ABL Revolver [Member]

ABL Revolver [Member]

ABL Revolver [Member]

ABL Revolver [Member]

ABL Revolver [Member]

Novelis Korea Bank Loan [Member]

Novelis Korea Bank Loan [Member]

Four-year Secured Term Loan Credit Facility [Member]

Floating Rate Term Loan Facility, due March 2017 [Member]

Floating Rate Term Loan Facility, due March 2017 [Member]

Capital Lease Obligations [Member]

B N D E S Loans Due December 2018 Through April 2021 [Member]

USD ($)

USD ($)

Minimum [Member]

Maximum [Member]

LIBOR [Member]

LIBOR [Member]

Prime [Member]

Prime [Member]

USD ($)

KRW

ABL Facility [Member]

ABL Facility [Member]

ABL Facility [Member]

CHF

BRL

Minimum [Member]

Maximum [Member]

Minimum [Member]

Maximum [Member]

USD ($)

LIBOR [Member]

Minimum [Member]

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Principal amount

'

'

'

'

'

'

'

'

'

$160,000,000

162,000,000,000

$1,700,000,000

'

'

'

27,000,000

Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments

'

'

'

'

'

'

'

'

'

'

'

'

'

'

31,000,000

'

Debt instrument, term

'5 years

'5 years

'

'

'

'

'

'

'

'

'

'4 years

'

'

'

'

Current borrowing capacity

1,000,000,000

'

1,000,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Potential additional borrowing capacity

500,000,000

'

500,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Description of variable rate basis

'LIBOR

'LIBOR

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Variable rate, floor

'

'

'

'

'

'

'

'

'

'

'

'

1.00%

'

'

'

Basis spread on variable rate

'

'

'

'

'

1.75%

2.25%

0.75%

1.25%

'

'

'

'

2.75%

'

'

Debt covenant, minimum fixed charge coverage ratio

'

'

'

1

1.25

'

'

'

'

'

'

'

'

'

'

'

Debt covenant, minimum amount for excess availability under ABL revolver

'

'

$110,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt covenant, percentage applied on lesser of ABL revolver commitment and applicable borrowing base

'

'

15.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of days preceding maturity date

'

'90 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt instrument, minimum excess availability percentage

'

'

'

'

25.00%

'

'

'

'

'

'

'

'

'

'

'

Debt instrument, minimum borrowing commitment

'

'

'

'

20.00%

'

'

'

'

'

'

'

'

'

'

'

Debt_ShortTerm_Borrowings_Deta

Debt (Short-Term Borrowings) (Details)

Jun. 30, 2014

Mar. 31, 2014

31-May-13

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Mar. 31, 2014

Mar. 31, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

USD ($)

USD ($)

Facilities

First Korean Revolver [Member]

First Korean Revolver [Member]

Novelis Brazil Loan [Member]

Novelis Korea Bank Loan [Member]

Novelis Korea Bank Loan [Member]

Novelis Vietnam Loan [Member]

Novelis Vietnam Loan [Member]

Bank Overdrafts [Member]

Novelis Korea Bank Loan Borrowing Capacity [Member]

Novelis Korea Bank Loan Borrowing Capacity [Member]

Novelis Korea Bank Loan Borrowing Capacity [Member]

Novelis Korea Bank Loan Borrowing Capacity [Member]

Novelis Korea Bank Loan Borrowing Capacity [Member]

Novelis Korea Bank Loan Borrowing Capacity [Member]

Novelis Korea Bank Loan Borrowing Capacity [Member]

Novelis Korea Bank Loan Borrowing Capacity [Member]

Novelis Korea Bank Loan Borrowing Capacity [Member]

Novelis Korea Bank Loan Borrowing Capacity [Member]

Novelis Korea Bank Loan Borrowing Capacity [Member]

ABL Facility [Member]

ABL Facility [Member]

Facilities

USD ($)

KRW

USD ($)

USD ($)

KRW

USD ($)

VND

USD ($)

First Korean Revolver [Member]

First Korean Revolver [Member]

Second Korean Revolver [Member]

Second Korean Revolver [Member]

Third Korean Revolver [Member]

Third Korean Revolver [Member]

Third Korean Revolver [Member]

Fifth Korean Revolver [Member]

Fifth Korean Revolver [Member]

Fourth Korean Revolver [Member]

Fourth Korean Revolver [Member]

USD ($)

Short-term Loan [Member]

USD ($)

KRW

USD ($)

KRW

USD ($)

KRW

USD ($)

USD ($)

KRW

USD ($)

KRW

USD ($)

Facilities

Facilities

Short-term Debt [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Short-term borrowings

$956,000,000

$723,000,000

'

'

'

$171,000,000

$57,000,000

58,000,000,000

$17,000,000

370,000,000,000

$1,000,000

$22,000,000

23,000,000,000

$49,000,000

50,000,000,000

$59,000,000

60,000,000,000

'

$30,000,000

30,000,000,000

$16,000,000

16,000,000,000

'

$710,000,000

Short-term debt, weighted average interest rate

3.58%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Letters of credit outstanding amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

12,000,000

'

Remaining borrowing capacity

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

278,000,000

'

Line of credit facility, number of instruments entered

2

'

2

'

'

'

'

'

'

'

'

1

1

'

'

'

'

1

'

'

'

'

'

'

Basis spread on variable rate

'

'

'

'

'

'

'

'

'

'

'

1.60%

1.60%

1.25%

1.25%

1.25%

1.25%

1.25%

'

'

1.60%

1.60%

'

'

Line of credit facility, amount outstanding

$0

'

'

$7,000,000

8,000,000,000

'

'

'

'

'

'

'

'

'

'

'

'

$0

'

'

'

'

'

'

Debt_Senior_Notes_Details

Debt (Senior Notes) (Details) (USD $)	Dec. 17, 2010
8.375% Senior Notes, due December 2017 [Member]	'
Debt Instrument [Line Items]	'
Principal amount	$1,100,000,000
Stated interest rate	8.38%
8.75% Senior Notes, due December 2020 [Member]	'
Debt Instrument [Line Items]	'
Principal amount	$1,400,000,000
Stated interest rate	8.75%

Debt_Korean_Bank_Loans_Details

Debt (Korean Bank Loans) (Details) (Novelis Korea Bank Loan [Member])	Jun. 30, 2014	Jun. 30, 2014	Jun. 30, 2014	Jun. 30, 2014
	USD ($)	KRW	Korea 91-day CD rate [Member]	Korea 91-day CD rate [Member]
			Minimum [Member]	Maximum [Member]
Debt Instrument [Line Items]	'	'	'	'
Principal amount	$160,000,000	162,000,000,000	'	'
Long-term debt, current maturities	$64,000,000	'	'	'
Stated interest rate	3.61%	3.61%	'	'
Basis spread on variable rate	'	'	0.80%	1.41%
Weighted average interest rate	3.58%	3.58%	'	'

Debt_Debt_Brazil_BNDES_Loans_D

Debt Debt (Brazil BNDES Loans) (Details) (BNDES Loans due February 2015 through April 2021 [Member], USD $)	Jun. 30, 2014
BNDES Loans due February 2015 through April 2021 [Member]	'
Debt Instrument [Line Items]	'
Principal amount	$12,000,000
Weighted average interest rate	6.29%
Long-term debt, current maturities	$3,000,000

Debt_Other_Longterm_Debt_Detai

Debt (Other Long-term Debt) (Details)	1 Months Ended			12 Months Ended			1 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2004	Dec. 31, 2004	Jun. 30, 2014	Mar. 31, 2013	Jun. 30, 2014	Jun. 30, 2014	Dec. 31, 2004	Jun. 30, 2014
	USD ($)	CHF	Capital Lease Obligations [Member]	Information Technology [Member]	Information Technology [Member]	Other Capital Leases [Member]	Alcan [Member]	Alcan [Member]
			CHF		USD ($)	USD ($)		USD ($)
Debt Instrument [Line Items]	'	'	'	'	'	'	'	'
Capital lease term	'	'	'	'5 years	'	'	'15 years	'
Weighted average interest rate	'	'	'	'	'	'	7.50%	'
Quarterly capital lease payments	$1.90	1.7	'	'	'	'	'	'
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments	'	'	31	'	$10	$5	'	$35

ShareBased_Compensation_Detail

Share-Based Compensation (Details) (2010 LTIP [Member], USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
2010 LTIP [Member]	'	'
Share-based Compensation Costs [Line Items]	'	'
Total compensation expense	$4	$13

ShareBased_Compensation_Detail1

Share-Based Compensation (Details 1)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2014	Jun. 30, 2014
	USD ($)	RSUs [Member]	RSUs [Member]
		USD ($)	INR
Number of RSUs	'	'	'
Outstanding as of beginning of period (shares)	'	4,490,860	4,490,860
Granted (shares)	'	1,455,206	1,455,206
Exercised (shares)	'	-682,361	-682,361
Forteited/Cancelled (shares)	'	-80,833	-80,833
Outstanding as of end of period (shares)	'	5,182,872	5,182,872
Grant Date Fair Value	'	'	'
Outstanding as of beginning of period (Indian Rupees per share)	'	'	120.42
Granted (Indian Rupees per share)	'	'	145.5
Exercised (Indian Rupees per share)	'	'	191.98
Forfeited/Cancelled (Indian Rupees per share)	'	'	143.19
Outstanding as of end of period (Indian Rupees per share)	'	'	118.47
Aggregate Intrinsic Value, Outstanding as of beginning of period	'	$11	'
Aggregate Intrinsic Value, Granted	'	0	'
Aggregate Intrinsic Value, Exercised	'	0	'
Aggregate Intrinsic Value, Forfeited/Cancelled	0	'	'
Aggregate Intrinsic Value, Outstanding as of end of period	'	$15	'

ShareBased_Compensation_ShareB

Share-Based Compensation Share-Based Compensation (Details 2) (SARs [Member])	3 Months Ended			12 Months Ended		3 Months Ended	12 Months Ended
In Millions, except Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Mar. 31, 2014	Jun. 30, 2014	Mar. 31, 2014
		Hindalco SARs [Member]	Hindalco SARs [Member]	Hindalco SARs [Member]	Hindalco SARs [Member]	Novelis SARs [Member]	Novelis SARs [Member]
		USD ($)	INR	USD ($)	INR	USD ($)	USD ($)
Number of SARs	'	'	'	'	'	'	'
Outstanding as of beginning of period (shares)	'	21,635,392	21,635,392	'	'	668,402	'
Granted (shares)	'	4,868,698	4,868,698	'	'	376,173	'
Exercised (shares)	'	-4,128,272	-4,128,272	'	'	-12,244	'
Forfeited/Cancelled (shares)	'	-730,823	-730,823	'	'	-33,760	'
Outstanding as of end of period (shares)	'	21,644,995	21,644,995	21,635,392	21,635,392	998,571	668,402
Shares exercisable as of end of period	'	8,339,534	8,339,534	'	'	223,623	'
Weighted Average Exercise Price	'	'	'	'	'	'	'
Outstanding as of beginning of period	'	'	112.26	'	'	$90.09	'
Granted	'	'	145.5	'	'	$94.40	'
Exercised	'	'	89.97	'	'	$66.46	'
Forfeited/Cancelled	'	'	131.29	'	'	$83.77	'
Outstanding as of end of period	'	'	123.35	'	112.26	$92.22	$90.09
Exercisable as of end of period	'	'	121.52	'	'	$89	'
Weighted Average Remaining Contractual Term, Outstanding as of beginning of period	'	'4 years 11 months	'4 years 11 months	'4 years 4 months	'4 years 4 months	'5 years 9 months	'5 years 4 months
Weighted Average Remaining Contractual Term, Granted	'7 years	'7 years 0 months	'7 years 0 months	'	'	'7 years 0 months	'
Weighted Average Remaining Contractual Term, Outstanding as of end of period	'	'4 years 11 months	'4 years 11 months	'4 years 4 months	'4 years 4 months	'5 years 9 months	'5 years 4 months
Weighted Average Remaining Contractual Term, Exercisable as of end of period	'	'3 years 4 months	'3 years 4 months	'	'	'4 years 10 months	'
Aggregate Intrinsic Value, Outstanding as of beginning of period	'	$13	'	'	'	$2	'
Aggregate Intrinsic Value, Granted	'	0	'	'	'	0	'
Aggregate Intrinsic Value, Outstanding as of end of period	'	17	'	13	'	4	2
Aggregate Intrinsic Value, Exercisable as of end of period	'	$8	'	'	'	$2	'

ShareBased_Compensation_Detail2

Share-Based Compensation (Details 3) (SARs [Member])	3 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Hindalco SARs [Member]	'	'
Assumptions used in estimating fair value of SARs	'	'
Dividend yield	0.61%	1.40%
Hindalco SARs [Member] | Minimum [Member]	'	'
Assumptions used in estimating fair value of SARs	'	'
Risk-free interest rate	8.56%	7.63%
Volatility	43.00%	39.00%
Hindalco SARs [Member] | Maximum [Member]	'	'
Assumptions used in estimating fair value of SARs	'	'
Risk-free interest rate	8.78%	7.75%
Volatility	55.00%	52.00%
Novelis SARs [Member]	'	'
Assumptions used in estimating fair value of SARs	'	'
Dividend yield	0.00%	0.00%
Novelis SARs [Member] | Minimum [Member]	'	'
Assumptions used in estimating fair value of SARs	'	'
Risk-free interest rate	1.21%	1.00%
Volatility	30.00%	31.00%
Novelis SARs [Member] | Maximum [Member]	'	'
Assumptions used in estimating fair value of SARs	'	'
Risk-free interest rate	2.10%	1.66%
Volatility	43.00%	41.00%

ShareBased_Compensation_Detail3

Share-Based Compensation (Details Textual) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Share Based Compensation [Abstract]	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Total Share-based Liabilities Paid	$5	$13
SARs [Member]	'	'
Share Based Compensation [Abstract]	'	'
Vesting rate	25.00%	'
Expiration period (years)	'7 years	'
Terms of award	'The amount of cash paid to settle Hindalco SARs and Novelis SARs are limited to two and a half or three times the target payout	'
Unrecognized compensation expense, weighted average period of recognition (years)	'2 years 2 months	'
SARs [Member] | Hindalco SARs [Member]	'	'
Share Based Compensation [Abstract]	'	'
Expiration period (years)	'7 years 0 months	'
Unrecognized compensation expense	15	'
Unrecognized compensation expense, weighted average period of recognition (years)	'2 years 1 month	'
SARs [Member] | Novelis SARs [Member]	'	'
Share Based Compensation [Abstract]	'	'
Expiration period (years)	'7 years 0 months	'
Unrecognized compensation expense	17	'
SARs [Member] | Minimum [Member]	'	'
Share Based Compensation [Abstract]	'	'
Vesting rate based on targeted EBITDA	75.00%	'
RSUs [Member]	'	'
Share Based Compensation [Abstract]	'	'
Terms of award	'The payout on the RSUs is limited to three times the market value of one Hindalco share measured on the original date of grant.	'
Vesting period (years)	'3 years	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Total Share-based Liabilities Paid	2	1
Unrecognized compensation expense	$10	'
Unrecognized compensation expense, weighted average period of recognition (years)	'1 year 9 months	'

Postretirement_Benefit_Plans_D

Postretirement Benefit Plans (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Pension Benefit Plans [Member]	'	'
Components of net periodic benefit cost for postretirement benefit plans	'	'
Service cost	$11	$13
Interest cost	17	16
Expected return on assets	-17	-16
Amortization-losses	6	5
Amortization — prior service credit, net	-1	0
Termination benefits / curtailments	1	0
Net periodic benefit cost	17	18
Other Benefit Plans [member]	'	'
Components of net periodic benefit cost for postretirement benefit plans	'	'
Service cost	1	3
Interest cost	1	2
Expected return on assets	0	0
Amortization-losses	2	1
Amortization — prior service credit, net	-10	0
Termination benefits / curtailments	-2	0
Net periodic benefit cost	($8)	$6

Postretirement_Benefit_Plans_D1

Postretirement Benefit Plans (Details 1) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Contributions to employee benefit plans	'	'
Funded pension plans	$4	$6
Unfunded pension plans	1	2
Savings and defined contribution pension plans	6	5
Total contributions	$11	$13

Postretirement_Benefit_Plans_D2

Postretirement Benefit Plans (Details Textual) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014
Compensation and Retirement Disclosure [Abstract]	'
Expected long-term rate of return on plan assets	6.10%
Defined Benefit Plan, Plan Amendments	$11
Maximum amortization period of unfunded actuarial liability	'15 years 0 months
Expected additional contribution to funded pension plan	30
Expected additional contribution to unfunded pension plan	13
Expected additional contribution to savings and defined contribution plans	$16

Currency_Gains_Losses_Details

Currency (Gains) Losses (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Currency (gains) losses included in other income expense	'	'
(Gain) loss on remeasurement of monetary assets and liabilities, net	$11	($18)
Loss released from accumulated other comprehensive income	0	1
(Gain) loss recognized on balance sheet remeasurement currency exchange contracts, net	-11	12
Currency (gains) losses, net	$0	($5)

Currency_Gains_Losses_Details_

Currency (Gains) Losses (Details 1) (USD $)	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Mar. 31, 2014
Currency gains included in AOCI, net of tax and Non controlling interests	'	'
Cumulative currency translation adjustment - beginning of period	$90	($30)
Effect of changes in exchange rates	27	120
Cumulative currency translation adjustment - end of period	$117	$90

Financial_Instruments_and_Comm2

Financial Instruments and Commodity Contracts (Details) (USD $)	Jun. 30, 2014		Mar. 31, 2014
In Millions, unless otherwise specified
Assets	'		'
Derivative Assets, Current	$67		$51
Derivative Assets, Noncurrent	9		4
Liabilities	'		'
Derivative Liabilities, Current	-65		-60
Derivative Liabilities, Noncurrent	-15	[1]	-19	[1]
Net Fair Value Assets/Liabilities	-4		-24
Designated as hedging instrument [Member]	'		'
Assets	'		'
Derivative Assets, Current	25		22
Derivative Assets, Noncurrent	9		4
Liabilities	'		'
Derivative Liabilities, Current	-21		-22
Derivative Liabilities, Noncurrent	-4	[1]	-6	[1]
Net Fair Value Assets/Liabilities	9		-2
Designated as hedging instrument [Member] | Cash flow hedges [Member] | Aluminium contracts [Member]	'		'
Assets	'		'
Derivative Assets, Current	0		4
Derivative Assets, Noncurrent	0		0
Liabilities	'		'
Derivative Liabilities, Current	-13		-7
Derivative Liabilities, Noncurrent	0	[1]	0	[1]
Net Fair Value Assets/Liabilities	-13		-3
Designated as hedging instrument [Member] | Cash flow hedges [Member] | Currency exchange contracts [Member]	'		'
Assets	'		'
Derivative Assets, Current	23		15
Derivative Assets, Noncurrent	9		4
Liabilities	'		'
Derivative Liabilities, Current	-7		-13
Derivative Liabilities, Noncurrent	-4	[1]	-6	[1]
Net Fair Value Assets/Liabilities	21		0
Designated as hedging instrument [Member] | Cash flow hedges [Member] | Energy contracts [Member]	'		'
Assets	'		'
Derivative Assets, Current	2		3
Derivative Assets, Noncurrent	0		0
Liabilities	'		'
Derivative Liabilities, Current	0		0
Derivative Liabilities, Noncurrent	0	[1]	0	[1]
Net Fair Value Assets/Liabilities	2		3
Designated as hedging instrument [Member] | Cash flow hedges [Member] | Interest rate swaps [Member]	'		'
Assets	'		'
Derivative Assets, Current	0		'
Derivative Assets, Noncurrent	0		'
Liabilities	'		'
Derivative Liabilities, Current	-1		'
Derivative Liabilities, Noncurrent	0	[1]	'
Net Fair Value Assets/Liabilities	-1		'
Designated as hedging instrument [Member] | Net investment hedges [Member] | Currency exchange contracts [Member]	'		'
Assets	'		'
Derivative Assets, Current	'		0
Derivative Assets, Noncurrent	'		0
Liabilities	'		'
Derivative Liabilities, Current	'		-1
Derivative Liabilities, Noncurrent	'		0	[1]
Net Fair Value Assets/Liabilities	'		-1
Designated as hedging instrument [Member] | Fair value hedging [Member] | Aluminium contracts [Member]	'		'
Assets	'		'
Derivative Assets, Current	'		0
Derivative Assets, Noncurrent	'		0
Liabilities	'		'
Derivative Liabilities, Current	'		-1
Derivative Liabilities, Noncurrent	'		0	[1]
Net Fair Value Assets/Liabilities	'		-1
Not designated as hedging instrument [Member]	'		'
Assets	'		'
Derivative Assets, Current	42		29
Derivative Assets, Noncurrent	0		0
Liabilities	'		'
Derivative Liabilities, Current	-44		-38
Derivative Liabilities, Noncurrent	-11	[1]	-13	[1]
Net Fair Value Assets/Liabilities	-13		-22
Not designated as hedging instrument [Member] | Aluminium contracts [Member]	'		'
Assets	'		'
Derivative Assets, Current	16		19
Derivative Assets, Noncurrent	0		0
Liabilities	'		'
Derivative Liabilities, Current	-29		-28
Derivative Liabilities, Noncurrent	0	[1]	0	[1]
Net Fair Value Assets/Liabilities	-13		-9
Not designated as hedging instrument [Member] | Currency exchange contracts [Member]	'		'
Assets	'		'
Derivative Assets, Current	26		9
Derivative Assets, Noncurrent	0		0
Liabilities	'		'
Derivative Liabilities, Current	-9		-3
Derivative Liabilities, Noncurrent	0	[1]	0	[1]
Net Fair Value Assets/Liabilities	17		6
Not designated as hedging instrument [Member] | Energy contracts [Member]	'		'
Assets	'		'
Derivative Assets, Current	0		1
Derivative Assets, Noncurrent	0		0
Liabilities	'		'
Derivative Liabilities, Current	-6		-7
Derivative Liabilities, Noncurrent	-11	[1]	-13	[1]
Net Fair Value Assets/Liabilities	($17)		($19)
[1]	The noncurrent portions of derivative assets and liabilities are included in “Other long-term assets-third parties” and in “Other long-term liabilities” respectively, in the accompanying condensed consolidated balance sheets

Financial_Instruments_and_Comm3

Financial Instruments and Commodity Contracts (Details 1) (Aluminum forward purchase contracts [Member], Fair value hedging [Member], Designated as hedging instrument [Member], USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013
Aluminum forward purchase contracts [Member] | Fair value hedging [Member] | Designated as hedging instrument [Member]	'		'
Derivative [Line Items]	'		'
Fair Value Hedges of Metal Price Risk, Derivative Contracts	$1		($3)
Fair Value Hedges of Metal Price Risk, Designated Hedged Items	-1		3
Net Ineffectiveness	$0	[1]	$0	[1]
[1]	Effective portion is recorded in "Net sales" and net ineffectiveness in "Other expense (income), net"

Financial_Instruments_and_Comm4

Financial Instruments and Commodity Contracts Financial Instruments and Commodity Contracts (Details 2)	Jun. 30, 2014	Mar. 31, 2014
	Mg	Mg
Aluminium contracts [Member]	'	'
Derivative [Line Items]	'	'
Notional amount (in tons)	-343,000	-302,000
Designated as hedging instrument [Member] | Aluminum forward purchase contracts [Member] | Cash flow hedges [Member]	'	'
Derivative [Line Items]	'	'
Notional amount (in tons)	3,000	16,000
Designated as hedging instrument [Member] | Aluminum forward purchase contracts [Member] | Fair value hedging [Member]	'	'
Derivative [Line Items]	'	'
Notional amount (in tons)	5,000	9,000
Designated as hedging instrument [Member] | Aluminum foward sales contracts [Member] | Cash flow hedges [Member]	'	'
Derivative [Line Items]	'	'
Notional amount (in tons)	-262,000	-222,000
Designated as hedging instrument [Member] | Aluminium contracts [Member] | Fair value hedging [Member]	'	'
Derivative [Line Items]	'	'
Notional amount (in tons)	5,000	9,000
Not designated as hedging instrument [Member] | Aluminium contracts [Member]	'	'
Derivative [Line Items]	'	'
Notional amount (in tons)	-89,000	-105,000

Financial_Instruments_and_Comm5

Financial Instruments and Commodity Contracts (Details 3) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Total gain (loss) recognized	$8		($23)
Other income (expense), net [Member]	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Balance sheet remeasurement currency exchange contracts	11		-13
Realized (losses) gains, net	-3		21
Unrealized gains (losses) on other derivative instruments, net	1		-12
Total gain (loss) recognized	9		-4
Other income (expense), net [Member] | Not designated as hedging instrument [Member]	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Total gain (loss) recognized	7		-14
Other income (expense), net [Member] | Designated as hedging instrument [Member]	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Total gain (loss) recognized	2	[1]	10	[1]
Other income (expense), net [Member] | Aluminium contracts [Member] | Not designated as hedging instrument [Member]	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Total gain (loss) recognized	-7		-2
Other income (expense), net [Member] | Currency exchange contracts [Member] | Not designated as hedging instrument [Member]	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Total gain (loss) recognized	12		-12
Other income (expense), net [Member] | Energy contracts [Member] | Not designated as hedging instrument [Member]	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Total gain (loss) recognized	$2	[2]	$0	[2]
[1]	Amount includes: forward market premium/discount excluded and hedging relationship ineffectiveness on designated aluminum and foreign currency capex contracts; releases to income from AOCI on balance sheet remeasurement contracts; and ineffectiveness on fair value hedges involving aluminum derivatives.
[2]	Includes amounts related to de-designated electricity swap.

Financial_Instruments_and_Comm6

Financial Instruments and Commodity Contracts (Details 4) (Cash flow hedges [Member], USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Amount of Gain (Loss) Recognized in OCI (Effective Portion)	$11	($24)
Amount of Gain (Loss) Recognized in “Other (Income) Expense, net” (Ineffective and Excluded Portion)	2	11
Aluminium contracts [Member]	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Amount of Gain (Loss) Recognized in OCI (Effective Portion)	-21	29
Amount of Gain (Loss) Recognized in “Other (Income) Expense, net” (Ineffective and Excluded Portion)	3	11
Currency exchange contracts [Member]	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Amount of Gain (Loss) Recognized in OCI (Effective Portion)	32	-51
Amount of Gain (Loss) Recognized in “Other (Income) Expense, net” (Ineffective and Excluded Portion)	-1	0
Energy contracts [Member]	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Amount of Gain (Loss) Recognized in OCI (Effective Portion)	0	-2
Amount of Gain (Loss) Recognized in “Other (Income) Expense, net” (Ineffective and Excluded Portion)	$0	$0

Financial_Instruments_and_Comm7

Financial Instruments and Commodity Contracts (Details 5) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Income tax provision	($24)		($3)
Net income	35		14
Cash flow hedges [Member]	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Amount of gain (loss) reclassified from AOCI into income/(expense) (effective portion)	0		22
Income tax provision	0		-7
Net income	0		15
Cash flow hedges [Member] | Electricity contracts [Member] | Other expense (income), net [Member]	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Amount of gain (loss) reclassified from AOCI into income/(expense) (effective portion)	-1	[1]	-1	[1]
Cash flow hedges [Member] | Electricity contracts [Member] | Cost of goods sold [Member]	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Amount of gain (loss) reclassified from AOCI into income/(expense) (effective portion)	1	[2],[3]	0	[2],[3]
Cash flow hedges [Member] | Aluminium contracts [Member] | Cost of goods sold [Member]	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Amount of gain (loss) reclassified from AOCI into income/(expense) (effective portion)	-6	[2]	21	[2]
Cash flow hedges [Member] | Aluminium contracts [Member] | Net sales [Member]	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Amount of gain (loss) reclassified from AOCI into income/(expense) (effective portion)	0		2
Cash flow hedges [Member] | Currency exchange contracts [Member] | Other expense (income), net [Member]	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Amount of gain (loss) reclassified from AOCI into income/(expense) (effective portion)	1		-1
Cash flow hedges [Member] | Currency exchange contracts [Member] | Cost of goods sold [Member]	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Amount of gain (loss) reclassified from AOCI into income/(expense) (effective portion)	1	[2]	1	[2]
Cash flow hedges [Member] | Currency exchange contracts [Member] | Net sales [Member]	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Amount of gain (loss) reclassified from AOCI into income/(expense) (effective portion)	$4		$0
[1]	Includes amounts related to de-designated electricity swap. AOCI related to this swap is amortized to income over the remaining term of the hedged item.
[2]	"Cost of goods sold" is exclusive of depreciation and amortization.
[3]	Includes amounts related to natural gas swaps.

Financial_Instruments_and_Comm8

Financial Instruments and Commodity Contracts (Details Textual)

3 Months Ended

3 Months Ended

3 Months Ended

3 Months Ended

3 Months Ended

3 Months Ended

In Millions, unless otherwise specified

Jun. 30, 2014

Mar. 31, 2014

Jun. 30, 2014

Mar. 31, 2014

Jun. 30, 2014

Mar. 31, 2014

Jun. 30, 2014

Mar. 31, 2014

Jun. 30, 2014

Mar. 31, 2014

Jun. 30, 2014

Jun. 30, 2014

Mar. 31, 2014

Jun. 30, 2014

Mar. 31, 2014

Jun. 30, 2014

Mar. 31, 2014

Jun. 30, 2014

Mar. 31, 2014

Jun. 30, 2014

Jun. 30, 2014

Mar. 31, 2014

Jun. 30, 2014

Mar. 31, 2014

Jun. 30, 2014

Jun. 30, 2014

Mar. 31, 2014

Mar. 31, 2014

Jun. 30, 2014

Mar. 31, 2014

Jun. 30, 2014

Mar. 31, 2014

Jun. 30, 2014

Mar. 31, 2014

Jun. 30, 2014

Mar. 31, 2014

Jun. 30, 2014

Mar. 31, 2014

Jun. 30, 2014

USD ($)

USD ($)

Designated as hedging instrument [Member]

Designated as hedging instrument [Member]

Not designated as hedging instrument [Member]

Not designated as hedging instrument [Member]

Aluminium contracts [Member]

Aluminium contracts [Member]

Aluminium contracts [Member]

Aluminium contracts [Member]

Aluminum foward sales contracts [Member]

Foreign currency [Member]

Foreign currency [Member]

Foreign currency [Member]

Foreign currency [Member]

Foreign currency [Member]

Foreign currency [Member]

Electricity swaps [Member]

Electricity swaps [Member]

Natural gas swaps [Member]

Natural gas swaps [Member]

Natural gas swaps [Member]

Natural gas swaps [Member]

Natural gas swaps [Member]

Interest rate swaps [Member]

Interest rate swaps [Member]

Interest rate swaps [Member]

Interest rate swaps [Member]

Fair value hedging [Member]

Fair value hedging [Member]

Fair value hedging [Member]

Fair value hedging [Member]

Cash flow hedges [Member]

Cash flow hedges [Member]

Cash flow hedges [Member]

Cash flow hedges [Member]

Cash flow hedges [Member]

Cash flow hedges [Member]

Cash flow hedges [Member]

USD ($)

USD ($)

USD ($)

USD ($)

Mg

Mg

Not designated as hedging instrument [Member]

Not designated as hedging instrument [Member]

Not designated as hedging instrument [Member]

Not designated as hedging instrument [Member]

Not designated as hedging instrument [Member]

Cash flow hedges [Member]

Cash flow hedges [Member]

Net investment hedges [Member]

Net investment hedges [Member]

Not designated as hedging instrument [Member]

Not designated as hedging instrument [Member]

Designated as hedging instrument [Member]

Designated as hedging instrument [Member]

Not designated as hedging instrument [Member]

Not designated as hedging instrument [Member]

Designated as hedging instrument [Member]

Designated as hedging instrument [Member]

Designated as hedging instrument [Member]

Designated as hedging instrument [Member]

Aluminium contracts [Member]

Aluminium contracts [Member]

Aluminum forward purchase contracts [Member]

Aluminum forward purchase contracts [Member]

Aluminium contracts [Member]

Aluminium contracts [Member]

Aluminum forward purchase contracts [Member]

Aluminum forward purchase contracts [Member]

Aluminum foward sales contracts [Member]

Aluminum foward sales contracts [Member]

Interest rate swaps [Member]

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

MMBTU

Korean Loans due December 2014 through 2015 [Member]

Korean Loans due December 2014 through 2015 [Member]

Korean Loans due December 2014 through 2015 [Member]

Korean Loans due December 2014 through 2015 [Member]

Designated as hedging instrument [Member]

Designated as hedging instrument [Member]

Designated as hedging instrument [Member]

Designated as hedging instrument [Member]

Designated as hedging instrument [Member]

Designated as hedging instrument [Member]

Designated as hedging instrument [Member]

Designated as hedging instrument [Member]

Designated as hedging instrument [Member]

Designated as hedging instrument [Member]

Designated as hedging instrument [Member]

Mg

Mg

MWh

MMBTU

MMBTU

MMBTU

USD ($)

KRW

USD ($)

KRW

Mg

USD ($)

Mg

Mg

USD ($)

USD ($)

Mg

Mg

Mg

Mg

USD ($)

Mg

Financial Instruments And Commodity Contracts [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Higher remaining maturity range

'

'

'

'

'

'

'

'

'

'

'0 years 5 months

'

'

'

'

'

'

'

'

'1 year

'

'

'

'

'

'

'

'

'

'

'2 years

'

'

'

'3 years

'

'2 years

'

'

Notional amount

'

'

'

'

'

'

-343,000

-302,000

-89,000

-105,000

'

'

'

'

'

'

'

'

'

'

8,100,000

9,500,000

1,100,000

1,500,000

'

'

'

'

5,000

9,000

5,000

9,000

'

'

3,000

16,000

-262,000

-222,000

'

Foreign currency, notional amounts

'

'

'

'

'

'

'

'

'

'

'

$767

$649

$582

$724

$53

$61

'

'

'

'

'

'

'

$134

136,000

$127

136,000

'

'

'

'

'

'

'

'

'

'

'

Notional outstanding

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fair value of swap asset (liability)

-4

-24

9

-2

-13

-22

'

'

-13

-9

'

'

'

'

'

'

'

17

-19

'

2

3

-1

'

'

'

'

'

'

-1

'

'

-13

-3

'

'

'

'

-1

Interest rate swaps, hedged amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

134

136,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Derivative, fixed interest rate

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

4.03%

4.03%

'

'

'

'

'

'

'

'

'

'

'

'

'

Expected reclassification of losses from AOCI to earnings

($2)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income (Loss) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
accumulated other comprehensive income [Line Items]	'	'
Accumulated Other Comprehensive Income (Loss), Net of Tax	($91)	($268)
Other Comprehensive Income (Loss), before Tax	34	-31
Other Comprehensive Income (Loss), Net of Tax	-3	-11
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	31	-42
Accumulated Other Comprehensive Income (Loss), Net of Tax	-60	-310
Currency Translation [Member]	'	'
accumulated other comprehensive income [Line Items]	'	'
Accumulated Other Comprehensive Income (Loss), Net of Tax	89	-33
Other Comprehensive Income (Loss), before Tax	26	-2
Other Comprehensive Income (Loss), Net of Tax	0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	26	-2
Accumulated Other Comprehensive Income (Loss), Net of Tax	115	-35
Cash Flow Hedges [Member]	'	'
accumulated other comprehensive income [Line Items]	'	'
Accumulated Other Comprehensive Income (Loss), Net of Tax	-20	-2
Other Comprehensive Income (Loss), before Tax	13	-29
Other Comprehensive Income (Loss), Net of Tax	0	15
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	13	-44
Accumulated Other Comprehensive Income (Loss), Net of Tax	-7	-46
Postretirement Benefit Plans [Member]	'	'
accumulated other comprehensive income [Line Items]	'	'
Accumulated Other Comprehensive Income (Loss), Net of Tax	-160	-233
Other Comprehensive Income (Loss), before Tax	-5	0
Other Comprehensive Income (Loss), Net of Tax	3	-4
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	-8	4
Accumulated Other Comprehensive Income (Loss), Net of Tax	($168)	($229)

Accumulated_Other_Comprehensiv3

Accumulated Other Comprehensive Income (Loss) AOCI Reclassifications Impact (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013
AOCI Reclassification [Line Items]	'		'
Income tax provision	($24)		($3)
Net income	35		14
Cash flow hedges [Member]	'		'
AOCI Reclassification [Line Items]	'		'
Amount of gain (loss) reclassified from AOCI into income/(expense) (effective portion)	0		22
Income tax provision	0		-7
Net income	0		15
Cash flow hedges [Member] | Electricity contracts [Member] | Other expense (income), net [Member]	'		'
AOCI Reclassification [Line Items]	'		'
Amount of gain (loss) reclassified from AOCI into income/(expense) (effective portion)	-1	[1]	-1	[1]
Cash flow hedges [Member] | Electricity contracts [Member] | Cost of goods sold [Member]	'		'
AOCI Reclassification [Line Items]	'		'
Amount of gain (loss) reclassified from AOCI into income/(expense) (effective portion)	1	[2],[3]	0	[2],[3]
Cash flow hedges [Member] | Aluminium contracts [Member] | Cost of goods sold [Member]	'		'
AOCI Reclassification [Line Items]	'		'
Amount of gain (loss) reclassified from AOCI into income/(expense) (effective portion)	-6	[2]	21	[2]
Cash flow hedges [Member] | Aluminium contracts [Member] | Net sales [Member]	'		'
AOCI Reclassification [Line Items]	'		'
Amount of gain (loss) reclassified from AOCI into income/(expense) (effective portion)	0		2
Cash flow hedges [Member] | Currency exchange contracts [Member] | Other expense (income), net [Member]	'		'
AOCI Reclassification [Line Items]	'		'
Amount of gain (loss) reclassified from AOCI into income/(expense) (effective portion)	1		-1
Cash flow hedges [Member] | Currency exchange contracts [Member] | Cost of goods sold [Member]	'		'
AOCI Reclassification [Line Items]	'		'
Amount of gain (loss) reclassified from AOCI into income/(expense) (effective portion)	1	[2]	1	[2]
Cash flow hedges [Member] | Currency exchange contracts [Member] | Net sales [Member]	'		'
AOCI Reclassification [Line Items]	'		'
Amount of gain (loss) reclassified from AOCI into income/(expense) (effective portion)	$4		$0
[1]	Includes amounts related to de-designated electricity swap. AOCI related to this swap is amortized to income over the remaining term of the hedged item.
[2]	"Cost of goods sold" is exclusive of depreciation and amortization.
[3]	Includes amounts related to natural gas swaps.

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)	Jun. 30, 2014		Mar. 31, 2014
In Millions, unless otherwise specified
Derivative assets and liabilities measured and recognized at fair value on recurring basis	'		'
Assets	$76		$55
Liabilities	-80		-79
Derivative Asset, Master Netting Adjustment	-21	[1]	-20	[1]
Derivative Liability, Master Netting Adjustment	21	[1]	20	[1]
Derivative Asset	55		35
Derivative Liability	59		59
Level 2 Instruments [Member]	'		'
Derivative assets and liabilities measured and recognized at fair value on recurring basis	'		'
Assets	76		55
Liabilities	-63		-60
Level 2 Instruments [Member] | Aluminium contracts [Member]	'		'
Derivative assets and liabilities measured and recognized at fair value on recurring basis	'		'
Assets	16		23
Liabilities	-42		-36
Level 2 Instruments [Member] | Currency exchange contracts [Member]	'		'
Derivative assets and liabilities measured and recognized at fair value on recurring basis	'		'
Assets	58		28
Liabilities	-20		-23
Level 2 Instruments [Member] | Energy contracts [Member]	'		'
Derivative assets and liabilities measured and recognized at fair value on recurring basis	'		'
Assets	2		4
Liabilities	0		-1
Level 2 Instruments [Member] | Interest Rate Swap [Member]	'		'
Derivative assets and liabilities measured and recognized at fair value on recurring basis	'		'
Assets	0		0
Liabilities	-1		0
Level 3 Instruments [Member]	'		'
Derivative assets and liabilities measured and recognized at fair value on recurring basis	'		'
Assets	0		0
Liabilities	-17		-19
Level 3 Instruments [Member] | Energy contracts [Member]	'		'
Derivative assets and liabilities measured and recognized at fair value on recurring basis	'		'
Assets	0		0
Liabilities	($17)		($19)
[1]	(A) Amounts represent the impact of legally enforceable master netting agreements that allow the Company to settle positive and negative positions with the same counterparties.

Fair_Value_Measurements_Detail1

Fair Value Measurements (Details 1) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014		Mar. 31, 2014
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'		'
Assets, Fair Value Disclosure, Recurring	$76		$55
Fair Value, Inputs, Level 2 [Member]	'		'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'		'
Assets, Fair Value Disclosure, Recurring	76		55
Level 3 Instruments [Member]	'		'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'		'
Assets, Fair Value Disclosure, Recurring	0		0
Reconciliation of fair value activity for Level 3 derivative contracts	'		'
Balance as of March 31, 2012	-19	[1]	'
Realized/unrealized gain included in earnings	4	[1],[2]	'
Settlements	-2	[1]	'
Balance as of September 30, 2012	($17)	[1]	'
[1]	Represents net derivative liabilities.
[2]	Included in “Other expense (income), net.”

Fair_Value_Measurements_Detail2

Fair Value Measurements (Details 2) (USD $)	Jun. 30, 2014	Mar. 31, 2014
In Millions, unless otherwise specified
Assets	'	'
Long-term receivables from related parties, carrying value	$21	$12
Long-term receivables from related parties, fair value	21	12
Liabilities	'	'
Total debt - third parties (excluding short term borrowings), carrying value	4,445	4,451
Total debt - third parties (excluding short term borrowings), fair value	$4,655	$4,734

Fair_Value_Measurements_Detail3

Fair Value Measurements (Details Textual) (USD $)	3 Months Ended
	Jun. 30, 2014
Fair Value Measurements [Abstract]	'
Derivatives, unit per hour	$1
Level 3 Instruments [Member]	'
Fair Value Measurements [Abstract]	'
Unrealized losses related to financial instruments	1,000,000
Electricity swaps [Member]	'
Fair Value Measurements [Abstract]	'
Average forward price (per megawatt hour)	59
Premium over forward prices in nearby observable market (per megawatt hour)	8
Actual swap settlement price (per megawatt hour)	51
Decrease in valuation per $1 per megawatt hour decline in electricity price	$1,000,000

Other_Income_Expense_Net_Detai

Other (Income) Expense, Net (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013
Other Income and Expenses [Abstract]	'		'
Foreign currency remeasurement (gains) losses, net	$0	[1]	($5)	[1]
Unrealized Gain (Loss) on Derivatives	1		-12
Loss (gain) on change in fair value of other unrealized derivative instruments, net	1		-12
(Gain) loss on change in fair value of other realized derivative instruments, net	3		-21
Loss on sale of assets	1		1
Gain (Loss) Related to Litigation Settlement	2	[2]	1	[2]
Interest income	-1		-1
Other, net	2		4
Other (income) expense, net	($5)		$10
[1]	(A)Includes “(Gain) loss recognized on balance sheet remeasurement currency exchange contracts, net.”
[2]	(B)See Note 16 – Commitments and Contingencies – Brazil Tax and Legal Matters for further details.

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Reconciliation of Canadian statutory tax rates	'	'
Pre-tax income (loss) before equity in net income of non-consolidated affiliates and noncontrolling interests	$61	$21
Canadian statutory tax rate	25.00%	26.00%
Provision at the Canadian statutory rate	15	5
Exchange translation items	4	-9
Exchange remeasurement of deferred income taxes	4	-15
Change in valuation allowances	11	37
Expense items not subject to tax	-1	-1
Dividends not subject to tax	-10	-14
Tax rate differences on foreign earnings	1	0
Income tax provision (benefit)	$24	$3
Effective tax rate	39.00%	14.00%

Income_Taxes_Details_Textual

Income Taxes (Details Textual) (USD $)	Jun. 30, 2014
In Millions, unless otherwise specified
Income Tax Details [Line Items]	'
Net deferred tax liability	$259
Gross deferred tax assets	877
Valuation allowance	429
Maximum amount by which reserves for interest and penalties for unrecognized tax benefits may decrease in the next 12 months	$3

Commitments_and_Contingencies_

Commitments and Contingencies (Details Textual) (USD $)

3 Months Ended

3 Months Ended

In Millions, unless otherwise specified

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Mar. 31, 2014

Jun. 30, 2014

Jun. 30, 2014

Mar. 31, 2014

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Other long-term liabilities [Member]

Other long-term liabilities [Member]

Accrued expenses and other current liabilities [Member]

Brazil tax matters [Member]

Brazil tax matters [Member]

Brazil tax matters [Member]

Brazil tax matters [Member]

Brazil tax matters [Member]

Brazil tax matters [Member]

Brazil tax matters [Member]

Brazil tax matters [Member]

Brazilian Tax Authorities and Other Third Parties [Member]

Brazilian Tax Authorities and Other Third Parties [Member]

Restructuring Action [Member]

Other long-term liabilities [Member]

Other long-term liabilities [Member]

Accrued expenses and other current liabilities [Member]

Accrued expenses and other current liabilities [Member]

Other long-term assets - third parties [Member]

Other long-term assets - third parties [Member]

Loss Contingencies [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Estimated range of loss, minimum

$0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Estimated range of loss, maximum

90

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Accrual for Environmental Loss Contingencies [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Accrual for environmental loss contingencies

7

'

'

'

'

'

'

'

'

'

'

'

'

'

'

18

Accrual for environmental loss contingencies, noncurrent

25

'

22

21

'

'

'

'

'

'

'

'

'

'

'

'

Accrual for environmental loss contingencies, current

'

'

'

'

3

'

'

'

'

'

'

'

'

'

'

'

Loss Contingency Accrual [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash deposits

'

'

'

'

'

'

'

'

'

'

'

7

6

'

'

'

Period for settlement payments

'

'

'

'

'

'180 months

'

'

'

'

'

'

'

'

'

'

Settlement liabilities

'

'

'

'

'

109

107

98

96

11

11

'

'

19

18

'

Loss on Brazilian tax litigation, net

($2)

[1]

($1)

[1]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

[1]

(B)See Note 16 – Commitments and Contingencies – Brazil Tax and Legal Matters for further details.

Segment_Major_Customer_and_Maj2

Segment, Major Customer and Major Supplier Information (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Mar. 31, 2014
Segment Reporting Information [Line Items]	'	'	'
Equity Method Investments	$607	'	$612
Assets Held-for-sale, Investment in and Advances to Non-consolidated Affiliates	40	'	39
Assets	9,304	'	9,114
Net sales	2,680	2,401	'
Depreciation and amortization	89	77	'
Income tax provision	24	3	'
Capital expenditures	138	181	'
Operating Segments [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	2,680	2,401	'
Depreciation and amortization	89	'	'
Income tax provision	24	'	'
Capital expenditures	138	'	'
Intersegment Elimination [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	0	0	'
Other And Eliminations [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Equity Method Investments	0	'	0
Assets Held-for-sale, Investment in and Advances to Non-consolidated Affiliates	0	'	0
Assets	58	'	47
Net sales	-31	-5	'
Other And Eliminations [Member] | Operating Segments [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	53	48	'
Depreciation and amortization	-7	-6	'
Income tax provision	6	4	'
Capital expenditures	-7	13	'
Other And Eliminations [Member] | Intersegment Elimination [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	-84	-53	'
South America [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Equity Method Investments	0	'	0
Assets Held-for-sale, Investment in and Advances to Non-consolidated Affiliates	40	'	39
Assets	1,714	'	1,583
Net sales	420	334	'
South America [Member] | Operating Segments [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	403	327	'
Depreciation and amortization	17	15	'
Income tax provision	12	-15	'
Capital expenditures	17	40	'
South America [Member] | Intersegment Elimination [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	17	7	'
Asia [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Equity Method Investments	0	'	0
Assets Held-for-sale, Investment in and Advances to Non-consolidated Affiliates	0	'	0
Assets	1,562	'	1,440
Net sales	556	485	'
Asia [Member] | Operating Segments [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	529	472	'
Depreciation and amortization	20	14	'
Income tax provision	3	4	'
Capital expenditures	20	65	'
Asia [Member] | Intersegment Elimination [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	27	13	'
North America [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Equity Method Investments	0	'	0
Assets Held-for-sale, Investment in and Advances to Non-consolidated Affiliates	0	'	0
Assets	2,805	'	2,998
Net sales	821	780	'
North America [Member] | Operating Segments [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	815	776	'
Depreciation and amortization	34	30	'
Income tax provision	-9	-1	'
Capital expenditures	19	27	'
North America [Member] | Intersegment Elimination [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	6	4	'
Europe [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Equity Method Investments	607	'	612
Assets Held-for-sale, Investment in and Advances to Non-consolidated Affiliates	0	'	0
Assets	3,165	'	3,046
Net sales	914	807	'
Europe [Member] | Operating Segments [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	880	778	'
Depreciation and amortization	25	24	'
Income tax provision	12	11	'
Capital expenditures	89	36	'
Europe [Member] | Intersegment Elimination [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	$34	$29	'

Segment_Major_Customer_and_Maj3

Segment, Major Customer and Major Supplier Information (Details 1) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Reconciliation of income from reportable segments to net income attributable to common shareholder	'	'
Depreciation and amortization	($89)	($77)
Interest expense and amortization of debt issuance costs	-81	-76
Adjustment to eliminate proportional consolidation	-8	-11
Unrealized gains (losses) on change in fair value of derivative instruments, net	1	-12
Realized (losses) gains on derivative instruments not included in segment income	-1	2
Gain on assets held for sale	-11	0
Restructuring and impairment, net	-6	-9
Other costs, net	-3	-4
Income (loss) before income taxes	59	17
Income tax (benefit) provision	24	3
Net income	35	14
Net income attributable to noncontrolling interests	0	0
Net income (loss) attributable to our common shareholder	35	14
North America [Member]	'	'
Reconciliation of income from reportable segments to net income attributable to common shareholder	'	'
Gross profit	64	46
Europe [Member]	'	'
Reconciliation of income from reportable segments to net income attributable to common shareholder	'	'
Gross profit	79	70
Asia [Member]	'	'
Reconciliation of income from reportable segments to net income attributable to common shareholder	'	'
Gross profit	37	46
South America [Member]	'	'
Reconciliation of income from reportable segments to net income attributable to common shareholder	'	'
Gross profit	$55	$42

Segment_Major_Customer_and_Maj4

Segment, Major Customer and Major Supplier Information (Details 2)	3 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Rexam [Member]	'	'
Revenue, Major Customer [Line Items]	'	'
Percentage of total net sales	18.00%	12.00%
Anheuser Busch [Member]	'	'
Revenue, Major Customer [Line Items]	'	'
Percentage of total net sales	8.00%	8.00%
Affiliates of Ball Corporation [Member]	'	'
Revenue, Major Customer [Line Items]	'	'
Percentage of total net sales	11.00%	10.00%

Segment_Major_Customer_and_Maj5

Segment, Major Customer and Major Supplier Information (Details 3) (Rio Tinto Alcan [Member])	3 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Rio Tinto Alcan [Member]	'	'
Purchases from primary supplier	'	'
Purchases from Rio Tinto Alcan as a percentage of total	15.00%	18.00%

Segment_Major_Customer_and_Maj6

Segment, Major Customer and Major Supplier Information (Details Textual)	3 Months Ended
	Jun. 30, 2014
	Customers
	Segments
	Plants
	Countries
Segment Reporting Information [Line Items]	'
Number of operating segments	4
Number of operating plants	24
Number of plants with recycling operations	10
Number of countries Company operates in	9
Number of major customers	3
North America [Member]	'
Segment Reporting Information [Line Items]	'
Number of operating plants	8
Number of fully dedicated recycling facilities	2
Number of plants with recycling operations	1
Number of countries Company operates in	2
Asia [Member]	'
Segment Reporting Information [Line Items]	'
Number of operating plants	3
Number of countries Company operates in	2
South America [Member]	'
Segment Reporting Information [Line Items]	'
Number of operating plants	3
Europe [Member]	'
Segment Reporting Information [Line Items]	'
Number of operating plants	10
Number of fully dedicated recycling facilities	2
Number of plants with recycling operations	2
Number of countries Company operates in	4

Supplemental_Information_Detai

Supplemental Information (Details1) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Supplemental cash flow information	'	'
Interest paid	$127	$124
Income taxes paid	$39	$31

Supplemental_Information_Detai1

Supplemental Information (Details Textual) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014
Supplemental Cash Flow Elements [Abstract]	'
Capital expenditures incurred but not yet paid	$59

Supplemental_Guarantor_Informa2

Supplemental Guarantor Information (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Supplemental guarantor information statements of operation	'	'
Net sales	$2,680	$2,401
Cost of goods sold (exclusive of depreciation and amortization)	2,329	2,098
Selling, general and administrative expenses	108	120
Depreciation and amortization	89	77
Research and development expenses	12	10
Interest expense and amortization of debt issuance costs	81	76
Gain on assets held for sale	-11	0
Restructuring and impairment, net	6	9
Equity in net (income) loss of non-consolidated affiliates	2	4
Equity in net (income) loss in consolidated subsidiaries	0	0
Other (income) expense, net	5	-10
Total expenses	2,621	2,384
Income (loss) before income taxes	59	17
Income tax (benefit) provision	24	3
Net income	35	14
Net Income (Loss) Attributable to Noncontrolling Interest	0	0
Net income (loss) attributable to our common shareholder	35	14
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	67	-29
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	1	-1
Comprehensive income (loss) attributable to our common shareholder	66	-28
Parent [Member]	'	'
Supplemental guarantor information statements of operation	'	'
Net sales	174	178
Cost of goods sold (exclusive of depreciation and amortization)	172	189
Selling, general and administrative expenses	-4	44
Depreciation and amortization	4	4
Research and development expenses	0	1
Interest expense and amortization of debt issuance costs	80	79
Gain on assets held for sale	-5	'
Restructuring and impairment, net	0	0
Equity in net (income) loss of non-consolidated affiliates	0	0
Equity in net (income) loss in consolidated subsidiaries	-90	-155
Other (income) expense, net	-20	2
Total expenses	137	164
Income (loss) before income taxes	37	14
Income tax (benefit) provision	2	0
Net income	35	14
Net Income (Loss) Attributable to Noncontrolling Interest	0	0
Net income (loss) attributable to our common shareholder	35	14
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	66	-28
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	0	0
Comprehensive income (loss) attributable to our common shareholder	66	-28
Guarantors [Member]	'	'
Supplemental guarantor information statements of operation	'	'
Net sales	2,235	1,962
Cost of goods sold (exclusive of depreciation and amortization)	1,950	1,717
Selling, general and administrative expenses	91	63
Depreciation and amortization	64	58
Research and development expenses	12	9
Interest expense and amortization of debt issuance costs	14	7
Gain on assets held for sale	-6	'
Restructuring and impairment, net	5	8
Equity in net (income) loss of non-consolidated affiliates	2	4
Equity in net (income) loss in consolidated subsidiaries	-9	-26
Other (income) expense, net	4	-29
Total expenses	2,127	1,811
Income (loss) before income taxes	108	151
Income tax (benefit) provision	18	-2
Net income	90	153
Net Income (Loss) Attributable to Noncontrolling Interest	0	0
Net income (loss) attributable to our common shareholder	90	153
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	74	172
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	0	0
Comprehensive income (loss) attributable to our common shareholder	74	172
Non-Guarantor [Member]	'	'
Supplemental guarantor information statements of operation	'	'
Net sales	685	626
Cost of goods sold (exclusive of depreciation and amortization)	621	557
Selling, general and administrative expenses	21	13
Depreciation and amortization	21	15
Research and development expenses	0	0
Interest expense and amortization of debt issuance costs	3	-1
Gain on assets held for sale	0	'
Restructuring and impairment, net	1	1
Equity in net (income) loss of non-consolidated affiliates	0	0
Equity in net (income) loss in consolidated subsidiaries	0	0
Other (income) expense, net	5	8
Total expenses	672	593
Income (loss) before income taxes	13	33
Income tax (benefit) provision	4	5
Net income	9	28
Net Income (Loss) Attributable to Noncontrolling Interest	0	0
Net income (loss) attributable to our common shareholder	9	28
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	44	6
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	1	-1
Comprehensive income (loss) attributable to our common shareholder	43	7
Eliminations [Member]	'	'
Supplemental guarantor information statements of operation	'	'
Net sales	-414	-365
Cost of goods sold (exclusive of depreciation and amortization)	-414	-365
Selling, general and administrative expenses	0	0
Depreciation and amortization	0	0
Research and development expenses	0	0
Interest expense and amortization of debt issuance costs	-16	-9
Gain on assets held for sale	0	'
Restructuring and impairment, net	0	0
Equity in net (income) loss of non-consolidated affiliates	0	0
Equity in net (income) loss in consolidated subsidiaries	99	181
Other (income) expense, net	16	9
Total expenses	-315	-184
Income (loss) before income taxes	-99	-181
Income tax (benefit) provision	0	0
Net income	-99	-181
Net Income (Loss) Attributable to Noncontrolling Interest	0	0
Net income (loss) attributable to our common shareholder	-99	-181
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	-117	-179
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	0	0
Comprehensive income (loss) attributable to our common shareholder	($117)	($179)

Supplemental_Guarantor_Informa3

Supplemental Guarantor Information (Details 1) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Mar. 31, 2014	Mar. 31, 2013
Current assets	'	'	'	'
Cash and cash equivalents	$337	$249	$509	$301
Accounts receivable, net	'	'	'	'
Accounts and Other Receivables, Net, Current	1,557	'	1,382	'
Accounts receivable - related parties	61	'	54	'
Inventories	1,295	'	1,173	'
Prepaid expenses and other current assets	114	'	101	'
Fair value of derivative instruments	67	'	51	'
Deferred income tax assets	101	'	101	'
Assets held for sale	72	'	102	'
Total current assets	3,604	'	3,473	'
Property, plant and equipment, net	3,575	'	3,513	'
Goodwill	608	'	611	'
Intangible assets, net	626	'	640	'
Investment in and advances to non-consolidated affiliates	607	'	612	'
Investments in Consolidated Subsidiaries	0	'	0	'
Fair value of derivative instruments, net of current portion	9	'	4	'
Deferred income tax assets	80	'	80	'
— third parties	183	'	173	'
— related parties	21	'	12	'
Total assets	9,304	'	9,114	'
Current liabilities	'	'	'	'
Current portion of long-term debt	95	'	92	'
Short-term borrowings	'	'	'	'
- third parties	956	'	723	'
- related parties	0	'	0	'
Accounts payable	'	'	'	'
— third parties	1,651	'	1,418	'
— related parties	56	'	53	'
Fair value of derivative instruments	65	'	60	'
Accrued expenses and other current liabilities	455	'	547	'
Accrued Expenses - Related Party	0	'	250	'
Deferred income tax liabilities	19	'	16	'
Liabilities of Assets Held-for-sale	0	'	11	'
Total current liabilities	3,297	'	3,170	'
Long-term debt, net of current portion	'	'	'	'
- third parties	4,350	'	4,359	'
- related parties	0	'	0	'
Deferred income tax liabilities	421	'	425	'
Accrued postretirement benefits	632	'	621	'
Other long-term liabilities	269	'	271	'
Total liabilities	8,969	'	8,846	'
Commitments and contingencies	'	'	'	'
Total temporary equity - intercompany	0	'	'	'
Shareholder's equity	'	'	'	'
Common stock	0	'	0	'
Additional paid-in capital	1,404	'	1,404	'
Retained Earnings (Accumulated Deficit)	-1,038	'	-1,073	'
Accumulated other comprehensive income (loss)	-60	-310	-91	-268
Total equity of our common shareholder	306	'	240	'
Noncontrolling interests	29	'	28	'
Total equity	335	'	268	'
Total liabilities and equity	9,304	'	9,114	'
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	1	-1	'	'
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	66	-28	'	'
Parent [Member]	'	'	'	'
Current assets	'	'	'	'
Cash and cash equivalents	4	14	4	4
Accounts receivable, net	'	'	'	'
Accounts and Other Receivables, Net, Current	21	'	15	'
Accounts receivable - related parties	333	'	1,093	'
Inventories	43	'	36	'
Prepaid expenses and other current assets	7	'	5	'
Fair value of derivative instruments	18	'	12	'
Deferred income tax assets	0	'	0	'
Assets held for sale	0	'	28	'
Total current assets	426	'	1,193	'
Property, plant and equipment, net	98	'	100	'
Goodwill	0	'	0	'
Intangible assets, net	18	'	19	'
Investment in and advances to non-consolidated affiliates	0	'	0	'
Investments in Consolidated Subsidiaries	3,322	'	3,273	'
Deferred income tax assets	0	'	0	'
— third parties	68	'	73	'
— related parties	1,331	'	844	'
Total assets	5,263	'	5,502	'
Current liabilities	'	'	'	'
Current portion of long-term debt	21	'	21	'
Short-term borrowings	'	'	'	'
- third parties	438	'	367	'
- related parties	32	'	32	'
Accounts payable	'	'	'	'
— third parties	30	'	35	'
— related parties	55	'	89	'
Fair value of derivative instruments	7	'	14	'
Accrued expenses and other current liabilities	42	'	104	'
Accrued Expenses - Related Party	0	'	250	'
Deferred income tax liabilities	0	'	0	'
Liabilities of Assets Held-for-sale	'	'	10	'
Total current liabilities	625	'	922	'
Long-term debt, net of current portion	'	'	'	'
- third parties	4,215	'	4,219	'
- related parties	49	'	49	'
Deferred income tax liabilities	0	'	0	'
Accrued postretirement benefits	42	'	44	'
Other long-term liabilities	26	'	28	'
Total liabilities	4,957	'	5,262	'
Total temporary equity - intercompany	0	'	'	'
Shareholder's equity	'	'	'	'
Common stock	0	'	0	'
Additional paid-in capital	1,404	'	1,404	'
Retained Earnings (Accumulated Deficit)	-1,038	'	-1,073	'
Accumulated other comprehensive income (loss)	-60	'	-91	'
Total equity of our common shareholder	306	'	240	'
Noncontrolling interests	0	'	0	'
Total equity	306	'	240	'
Total liabilities and equity	5,263	'	5,502	'
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	0	0	'	'
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	66	-28	'	'
Guarantors [Member]	'	'	'	'
Current assets	'	'	'	'
Cash and cash equivalents	207	164	372	196
Accounts receivable, net	'	'	'	'
Accounts and Other Receivables, Net, Current	1,247	'	1,121	'
Accounts receivable - related parties	159	'	193	'
Inventories	968	'	880	'
Prepaid expenses and other current assets	87	'	76	'
Fair value of derivative instruments	19	'	26	'
Deferred income tax assets	99	'	96	'
Assets held for sale	72	'	74	'
Total current assets	2,858	'	2,838	'
Property, plant and equipment, net	2,516	'	2,485	'
Goodwill	597	'	600	'
Intangible assets, net	604	'	617	'
Investment in and advances to non-consolidated affiliates	607	'	612	'
Investments in Consolidated Subsidiaries	658	'	612	'
Deferred income tax assets	27	'	28	'
— third parties	99	'	89	'
— related parties	70	'	61	'
Total assets	8,036	'	7,942	'
Current liabilities	'	'	'	'
Current portion of long-term debt	10	'	10	'
Short-term borrowings	'	'	'	'
- third parties	443	'	287	'
- related parties	88	'	809	'
Accounts payable	'	'	'	'
— third parties	1,066	'	912	'
— related parties	364	'	377	'
Fair value of derivative instruments	46	'	40	'
Accrued expenses and other current liabilities	331	'	358	'
Accrued Expenses - Related Party	9	'	4	'
Deferred income tax liabilities	19	'	16	'
Liabilities of Assets Held-for-sale	'	'	1	'
Total current liabilities	2,376	'	2,814	'
Long-term debt, net of current portion	'	'	'	'
- third parties	37	'	40	'
- related parties	1,272	'	788	'
Deferred income tax liabilities	415	'	419	'
Accrued postretirement benefits	431	'	422	'
Other long-term liabilities	234	'	236	'
Total liabilities	4,765	'	4,719	'
Total temporary equity - intercompany	1,681	'	'	'
Shareholder's equity	'	'	'	'
Common stock	0	'	0	'
Additional paid-in capital	0	'	0	'
Retained Earnings (Accumulated Deficit)	1,752	'	1,684	'
Accumulated other comprehensive income (loss)	-162	'	-142	'
Total equity of our common shareholder	1,590	'	1,542	'
Noncontrolling interests	0	'	0	'
Total equity	1,590	'	1,542	'
Total liabilities and equity	8,036	'	7,942	'
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	0	0	'	'
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	74	172	'	'
Non-Guarantor [Member]	'	'	'	'
Current assets	'	'	'	'
Cash and cash equivalents	126	71	133	101
Accounts receivable, net	'	'	'	'
Accounts and Other Receivables, Net, Current	289	'	246	'
Accounts receivable - related parties	88	'	57	'
Inventories	284	'	257	'
Prepaid expenses and other current assets	20	'	20	'
Fair value of derivative instruments	31	'	14	'
Deferred income tax assets	2	'	5	'
Assets held for sale	0	'	0	'
Total current assets	840	'	732	'
Property, plant and equipment, net	961	'	928	'
Goodwill	11	'	11	'
Intangible assets, net	4	'	4	'
Investment in and advances to non-consolidated affiliates	0	'	0	'
Investments in Consolidated Subsidiaries	0	'	0	'
Deferred income tax assets	53	'	52	'
— third parties	16	'	11	'
— related parties	0	'	0	'
Total assets	1,885	'	1,738	'
Current liabilities	'	'	'	'
Current portion of long-term debt	64	'	61	'
Short-term borrowings	'	'	'	'
- third parties	75	'	69	'
- related parties	0	'	0	'
Accounts payable	'	'	'	'
— third parties	555	'	471	'
— related parties	23	'	29	'
Fair value of derivative instruments	13	'	7	'
Accrued expenses and other current liabilities	82	'	85	'
Accrued Expenses - Related Party	4	'	2	'
Deferred income tax liabilities	0	'	0	'
Liabilities of Assets Held-for-sale	'	'	0	'
Total current liabilities	816	'	724	'
Long-term debt, net of current portion	'	'	'	'
- third parties	98	'	100	'
- related parties	59	'	56	'
Deferred income tax liabilities	6	'	6	'
Accrued postretirement benefits	159	'	155	'
Other long-term liabilities	9	'	7	'
Total liabilities	1,147	'	1,048	'
Total temporary equity - intercompany	0	'	'	'
Shareholder's equity	'	'	'	'
Common stock	0	'	0	'
Additional paid-in capital	0	'	0	'
Retained Earnings (Accumulated Deficit)	689	'	680	'
Accumulated other comprehensive income (loss)	20	'	-18	'
Total equity of our common shareholder	709	'	662	'
Noncontrolling interests	29	'	28	'
Total equity	738	'	690	'
Total liabilities and equity	1,885	'	1,738	'
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	1	-1	'	'
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	43	7	'	'
Eliminations [Member]	'	'	'	'
Current assets	'	'	'	'
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	'	'	'	'
Accounts and Other Receivables, Net, Current	0	'	0	'
Accounts receivable - related parties	-519	'	-1,289	'
Inventories	0	'	0	'
Prepaid expenses and other current assets	0	'	0	'
Fair value of derivative instruments	-1	'	-1	'
Deferred income tax assets	0	'	0	'
Assets held for sale	0	'	0	'
Total current assets	-520	'	-1,290	'
Property, plant and equipment, net	0	'	0	'
Goodwill	0	'	0	'
Intangible assets, net	0	'	0	'
Investment in and advances to non-consolidated affiliates	0	'	0	'
Investments in Consolidated Subsidiaries	-3,980	'	-3,885	'
Deferred income tax assets	0	'	0	'
— third parties	0	'	0	'
— related parties	-1,380	'	-893	'
Total assets	-5,880	'	-6,068	'
Current liabilities	'	'	'	'
Current portion of long-term debt	0	'	0	'
Short-term borrowings	'	'	'	'
- third parties	0	'	0	'
- related parties	-120	'	-841	'
Accounts payable	'	'	'	'
— third parties	0	'	0	'
— related parties	-386	'	-442	'
Fair value of derivative instruments	-1	'	-1	'
Accrued expenses and other current liabilities	0	'	0	'
Accrued Expenses - Related Party	-13	'	-6	'
Deferred income tax liabilities	0	'	0	'
Liabilities of Assets Held-for-sale	'	'	0	'
Total current liabilities	-520	'	-1,290	'
Long-term debt, net of current portion	'	'	'	'
- third parties	0	'	0	'
- related parties	-1,380	'	-893	'
Deferred income tax liabilities	0	'	0	'
Accrued postretirement benefits	0	'	0	'
Other long-term liabilities	0	'	0	'
Total liabilities	-1,900	'	-2,183	'
Total temporary equity - intercompany	-1,681	'	'	'
Shareholder's equity	'	'	'	'
Common stock	0	'	0	'
Additional paid-in capital	0	'	0	'
Retained Earnings (Accumulated Deficit)	-2,441	'	-2,364	'
Accumulated other comprehensive income (loss)	142	'	160	'
Total equity of our common shareholder	-2,299	'	-2,204	'
Noncontrolling interests	0	'	0	'
Total equity	-2,299	'	-2,204	'
Total liabilities and equity	-5,880	'	-6,068	'
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	0	0	'	'
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	($117)	($179)	'	'

Supplemental_Guarantor_Informa4

Supplemental Guarantor Information (Details 2) (USD $)	3 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Condensed Financial Statements, Captions [Line Items]	'	'
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	$59,000,000	$17,000,000
Net income	35,000,000	14,000,000
OPERATING ACTIVITIES	'	'
Net cash provided by (used in) operating activities	-24,000,000	-102,000,000
INVESTING ACTIVITIES	'	'
Capital expenditures	-138,000,000	-181,000,000
(Outflow) proceeds from related party loans receivable, net	'	0
Proceeds (outflow) from settlement of other undesignated derivative instruments, net	1,000,000	-6,000,000
Net cash used in investing activities	-119,000,000	-187,000,000
Proceeds from issuance of debt	'	'
- third parties	105,000,000	42,000,000
- related parties	0	0
Principal payments	'	'
- third parties	-53,000,000	-17,000,000
- related parties	0	'
Short-term borrowings, net	'	'
- third parties	166,000,000	219,000,000
- related parties	0	0
Payments of Capital Distribution	-250,000,000	0
Dividends, noncontrolling interest	0	0
Payments of Debt Issuance Costs	0	-7,000,000
Net cash (used in) provided by financing activities	-32,000,000	237,000,000
Net decrease in cash and cash equivalents	-175,000,000	-52,000,000
Effect of exchange rate changes on cash	3,000,000	0
Cash and cash equivalents — beginning of period	509,000,000	301,000,000
Cash and cash equivalents — end of period	337,000,000	249,000,000
Proceeds from Sale of Productive Assets	34,000,000	0
Proceeds from Sale of Assets, Related Parties	0	'
Outflows from investments in and advances to non–consolidated affiliates, net	16,000,000	0
Parent [Member]	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	37,000,000	14,000,000
Net income	35,000,000	14,000,000
OPERATING ACTIVITIES	'	'
Net cash provided by (used in) operating activities	-79,000,000	-134,000,000
INVESTING ACTIVITIES	'	'
Capital expenditures	-4,000,000	-4,000,000
(Outflow) proceeds from related party loans receivable, net	'	13,000,000
Proceeds (outflow) from settlement of other undesignated derivative instruments, net	3,000,000	2,000,000
Net cash used in investing activities	263,000,000	11,000,000
Proceeds from issuance of debt	'	'
- third parties	0	0
- related parties	0	0
Principal payments	'	'
- third parties	-5,000,000	-5,000,000
- related parties	0	'
Short-term borrowings, net	'	'
- third parties	71,000,000	145,000,000
- related parties	0	0
Payments of Capital Distribution	-250,000,000	'
Dividends, noncontrolling interest	0	0
Payments of Debt Issuance Costs	'	-7,000,000
Net cash (used in) provided by financing activities	-184,000,000	133,000,000
Net decrease in cash and cash equivalents	0	10,000,000
Effect of exchange rate changes on cash	0	0
Cash and cash equivalents — beginning of period	4,000,000	4,000,000
Cash and cash equivalents — end of period	4,000,000	14,000,000
Proceeds from Sale of Productive Assets	29,000,000	'
Proceeds from Sale of Assets, Related Parties	0	'
Outflows from investments in and advances to non–consolidated affiliates, net	-235,000,000	'
Guarantors [Member]	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	108,000,000	151,000,000
Net income	90,000,000	153,000,000
OPERATING ACTIVITIES	'	'
Net cash provided by (used in) operating activities	67,000,000	43,000,000
INVESTING ACTIVITIES	'	'
Capital expenditures	-114,000,000	-118,000,000
(Outflow) proceeds from related party loans receivable, net	'	0
Proceeds (outflow) from settlement of other undesignated derivative instruments, net	-9,000,000	-13,000,000
Net cash used in investing activities	-134,000,000	-131,000,000
Proceeds from issuance of debt	'	'
- third parties	95,000,000	41,000,000
- related parties	500,000,000	0
Principal payments	'	'
- third parties	-35,000,000	-12,000,000
- related parties	-17,000,000	'
Short-term borrowings, net	'	'
- third parties	96,000,000	74,000,000
- related parties	-721,000,000	-34,000,000
Payments of Capital Distribution	0	'
Dividends, noncontrolling interest	-15,000,000	-14,000,000
Payments of Debt Issuance Costs	'	0
Net cash (used in) provided by financing activities	-97,000,000	55,000,000
Net decrease in cash and cash equivalents	-164,000,000	-33,000,000
Effect of exchange rate changes on cash	-1,000,000	1,000,000
Cash and cash equivalents — beginning of period	372,000,000	196,000,000
Cash and cash equivalents — end of period	207,000,000	164,000,000
Proceeds from Sale of Productive Assets	5,000,000	'
Proceeds from Sale of Assets, Related Parties	0	'
Outflows from investments in and advances to non–consolidated affiliates, net	16,000,000	'
Non-Guarantor [Member]	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	13,000,000	33,000,000
Net income	9,000,000	28,000,000
OPERATING ACTIVITIES	'	'
Net cash provided by (used in) operating activities	3,000,000	3,000,000
INVESTING ACTIVITIES	'	'
Capital expenditures	-20,000,000	-59,000,000
(Outflow) proceeds from related party loans receivable, net	'	0
Proceeds (outflow) from settlement of other undesignated derivative instruments, net	7,000,000	5,000,000
Net cash used in investing activities	-13,000,000	-54,000,000
Proceeds from issuance of debt	'	'
- third parties	10,000,000	1,000,000
- related parties	3,000,000	21,000,000
Principal payments	'	'
- third parties	-13,000,000	0
- related parties	0	'
Short-term borrowings, net	'	'
- third parties	-1,000,000	0
- related parties	0	0
Payments of Capital Distribution	0	'
Dividends, noncontrolling interest	0	0
Payments of Debt Issuance Costs	'	0
Net cash (used in) provided by financing activities	-1,000,000	22,000,000
Net decrease in cash and cash equivalents	-11,000,000	-29,000,000
Effect of exchange rate changes on cash	4,000,000	-1,000,000
Cash and cash equivalents — beginning of period	133,000,000	101,000,000
Cash and cash equivalents — end of period	126,000,000	71,000,000
Proceeds from Sale of Productive Assets	0	'
Proceeds from Sale of Assets, Related Parties	0	'
Outflows from investments in and advances to non–consolidated affiliates, net	0	'
Eliminations [Member]	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	-99,000,000	-181,000,000
Net income	-99,000,000	-181,000,000
OPERATING ACTIVITIES	'	'
Net cash provided by (used in) operating activities	-15,000,000	-14,000,000
INVESTING ACTIVITIES	'	'
Capital expenditures	0	0
(Outflow) proceeds from related party loans receivable, net	'	-13,000,000
Proceeds (outflow) from settlement of other undesignated derivative instruments, net	0	0
Net cash used in investing activities	-235,000,000	-13,000,000
Proceeds from issuance of debt	'	'
- third parties	0	0
- related parties	-503,000,000	-21,000,000
Principal payments	'	'
- third parties	0	0
- related parties	17,000,000	'
Short-term borrowings, net	'	'
- third parties	0	0
- related parties	721,000,000	34,000,000
Payments of Capital Distribution	0	'
Dividends, noncontrolling interest	15,000,000	14,000,000
Payments of Debt Issuance Costs	'	0
Net cash (used in) provided by financing activities	250,000,000	27,000,000
Net decrease in cash and cash equivalents	0	0
Effect of exchange rate changes on cash	0	0
Cash and cash equivalents — beginning of period	0	0
Cash and cash equivalents — end of period	0	0
Proceeds from Sale of Productive Assets	0	'
Proceeds from Sale of Assets, Related Parties	0	'
Outflows from investments in and advances to non–consolidated affiliates, net	$235,000,000	'