Supplemental Guarantor Information (Details 2) (USD $) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended
	Jun. 30, 2012	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
OPERATING ACTIVITIES
Net cash provided by (used in) operating activities		$ 702	$ 203	$ 556
INVESTING ACTIVITIES
Capital expenditures		(717)	(775)	(516)
Proceeds from sales of assets, net - third parties	18	8	19	12
Proceeds from the sale of assets, net - related parties		8	2	4
Net (outflow) proceeds from investment in and advances to affiliates		(16)	3	(1)
(Outflow) proceeds from settlement of undesignated derivative instruments, net		15	4	59
Net cash used in investing activities		(702)	(747)	(442)
Proceeds from issuance of debt
— third parties		169	319	271
— related parties		0	0	0
Principal payments
— third parties		(164)	(97)	(22)
— related parties		0	0	0
Short-term borrowings, net
- third parties		208	332	2
- related parties		0	0	0
Return of capital		0		0
Proceeds from issuance of intercompany equity			0
Dividends, noncontrolling interests and intercompany		0	(2)	(1)
Acquisition of noncontrolling interest in Novelis Korea Ltd.		0	(9)	(344)
Debt issuance costs		(8)	(8)	(2)
Net cash provided by (used in) financing activities		205	535	(96)
Net increase (decrease) in cash and cash equivalents		205	(9)	18
Effect of exchange rate changes on cash		3	(7)	(12)
Cash and cash equivalents — beginning of period		301	317	311
Cash and cash equivalents — end of period		509	301	317
Parent [Member]
OPERATING ACTIVITIES
Net cash provided by (used in) operating activities		144	87	(170)
INVESTING ACTIVITIES
Capital expenditures		(22)	(11)	6
Proceeds from sales of assets, net - third parties		0	7	(1)
Proceeds from the sale of assets, net - related parties		0	0	0
Net (outflow) proceeds from investment in and advances to affiliates		(261)	(313)	326
(Outflow) proceeds from settlement of undesignated derivative instruments, net		(21)	13	3
Net cash used in investing activities		(304)	(304)	334
Proceeds from issuance of debt
— third parties		0	80	216
— related parties		0	49	0
Principal payments
— third parties		(19)	(92)	(16)
— related parties		0	0	0
Short-term borrowings, net
- third parties		162	205	0
- related parties		25	(10)	(13)
Return of capital		0		0
Proceeds from issuance of intercompany equity			0
Dividends, noncontrolling interests and intercompany		0	0	0
Acquisition of noncontrolling interest in Novelis Korea Ltd.			(9)	(344)
Debt issuance costs		(8)	(8)	(2)
Net cash provided by (used in) financing activities		160	215	(159)
Net increase (decrease) in cash and cash equivalents		0	(2)	5
Effect of exchange rate changes on cash		0	0	0
Cash and cash equivalents — beginning of period		4	6	1
Cash and cash equivalents — end of period		4	4	6
Guarantors [Member]
OPERATING ACTIVITIES
Net cash provided by (used in) operating activities		893	230	741
INVESTING ACTIVITIES
Capital expenditures		(492)	(491)	(362)
Proceeds from sales of assets, net - third parties		7	12	12
Proceeds from the sale of assets, net - related parties		8	2	4
Net (outflow) proceeds from investment in and advances to affiliates		(41)	(20)	12
(Outflow) proceeds from settlement of undesignated derivative instruments, net		21	4	38
Net cash used in investing activities		(497)	(493)	(296)
Proceeds from issuance of debt
— third parties		147	98	12
— related parties		0	9	348
Principal payments
— third parties		(143)	(5)	(6)
— related parties		0	(26)	(513)
Short-term borrowings, net
- third parties		44	127	1
- related parties		208	286	(174)
Return of capital		0		0
Proceeds from issuance of intercompany equity			1
Dividends, noncontrolling interests and intercompany		(479)	(237)	(112)
Acquisition of noncontrolling interest in Novelis Korea Ltd.			0	0
Debt issuance costs		0	0	0
Net cash provided by (used in) financing activities		(223)	253	(444)
Net increase (decrease) in cash and cash equivalents		173	(10)	1
Effect of exchange rate changes on cash		3	(9)	(19)
Cash and cash equivalents — beginning of period		196	215	233
Cash and cash equivalents — end of period		372	196	215
Non-Guarantors [Member]
OPERATING ACTIVITIES
Net cash provided by (used in) operating activities		233	202	200
INVESTING ACTIVITIES
Capital expenditures		(203)	(273)	(160)
Proceeds from sales of assets, net - third parties		1	0	1
Proceeds from the sale of assets, net - related parties		0	0	0
Net (outflow) proceeds from investment in and advances to affiliates		0	0	13
(Outflow) proceeds from settlement of undesignated derivative instruments, net		15	(13)	18
Net cash used in investing activities		(187)	(286)	(128)
Proceeds from issuance of debt
— third parties		22	141	43
— related parties		56	0	0
Principal payments
— third parties		(2)	0	0
— related parties		0	0	0
Short-term borrowings, net
- third parties		2	0	1
- related parties		0	(17)	0
Return of capital		(3)		0
Proceeds from issuance of intercompany equity			44
Dividends, noncontrolling interests and intercompany		(89)	(81)	(104)
Acquisition of noncontrolling interest in Novelis Korea Ltd.			0	0
Debt issuance costs		0	0	0
Net cash provided by (used in) financing activities		(14)	87	(60)
Net increase (decrease) in cash and cash equivalents		32	3	12
Effect of exchange rate changes on cash		0	2	7
Cash and cash equivalents — beginning of period		101	96	77
Cash and cash equivalents — end of period		133	101	96
Eliminations [Member]
OPERATING ACTIVITIES
Net cash provided by (used in) operating activities		(568)	(316)	(215)
INVESTING ACTIVITIES
Capital expenditures		0	0	0
Proceeds from sales of assets, net - third parties		0	0	0
Proceeds from the sale of assets, net - related parties		0	0	0
Net (outflow) proceeds from investment in and advances to affiliates		286	336	(352)
(Outflow) proceeds from settlement of undesignated derivative instruments, net		0	0	0
Net cash used in investing activities		286	336	(352)
Proceeds from issuance of debt
— third parties		0	0	0
— related parties		(56)	(58)	(348)
Principal payments
— third parties		0	0	0
— related parties		0	26	513
Short-term borrowings, net
- third parties		0	0	0
- related parties		(233)	(259)	187
Return of capital		3		0
Proceeds from issuance of intercompany equity			(45)
Dividends, noncontrolling interests and intercompany		568	316	215
Acquisition of noncontrolling interest in Novelis Korea Ltd.			0	0
Debt issuance costs		0	0	0
Net cash provided by (used in) financing activities		282	(20)	567
Net increase (decrease) in cash and cash equivalents		0	0	0
Effect of exchange rate changes on cash		0	0	0
Cash and cash equivalents — beginning of period		0	0	0
Cash and cash equivalents — end of period		$ 0	$ 0	$ 0