Share-Based Compensation (Details Textual) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Sep. 30, 2014	Sep. 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	$ 7	$ 15
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 3 months
SARs [Member] | Hindalco SARs [Member]
Share Based Compensation [Abstract]
Terms of award	P6Y7M
Unrecognized compensation expense	13
Unrecognized compensation expense, weighted average period of recognition (years)	2 years 2 months
SARs [Member] | Novelis SARs [Member]
Share Based Compensation [Abstract]
Terms of award	P6Y7M
Unrecognized compensation expense	15
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	3	1
Unrecognized compensation expense	$ 8
Unrecognized compensation expense, weighted average period of recognition (years)	1 year 6 months