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 Value		Fair Value		Carrying Value		Fair 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