Debt (Short-term Borrowings (Details) In Millions, unless otherwise specified	Mar. 31, 2015 USD ($)	Mar. 31, 2014 USD ($)	Mar. 31, 2015 China [Member] USD ($)	Mar. 31, 2015 China [Member] CNY	Mar. 31, 2015 Revolving Credit Facility [Member] Korea [Member] USD ($)	Mar. 31, 2015 Revolving Credit Facility [Member] Korea [Member] KRW	Mar. 31, 2015 ABL Revolver [Member] USD ($)	Mar. 31, 2015 Short-term Loan [Member] ABL Revolver [Member] USD ($)	Mar. 31, 2015 Novelis Korea Bank Loan [Member] USD ($)	Mar. 31, 2015 Novelis Korea Bank Loan [Member] KRW	Mar. 31, 2015 Novelis Brazil Loan [Member] USD ($)	Mar. 31, 2015 Novelis Vietnam Loan [Member] [Member] USD ($)	Mar. 31, 2015 Novelis Vietnam Loan [Member] [Member] VND	Mar. 31, 2015 Novelis China Loan [Member] USD ($)	Mar. 31, 2015 Novelis China Loan [Member] CNY	Mar. 31, 2015 Bank Overdrafts [Member] USD ($)
Debt Instrument [Line Items]
Short-term borrowings	$ 846	$ 723			$ 186	206,000		$ 609	$ 52	58,000	$ 166	$ 9	199,000	$ 8	48	$ 2
Letters of credit outstanding amount							8
Remaining borrowing capacity			$ 17	102			$ 307