Statement of Consolidated Comprehensive (Loss) Income (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Net (loss) income	$ (19)	$ 377	$ 80	$ 743
Other comprehensive (loss) income, net of tax:
Change in unrecognized net actuarial loss and prior service cost/benefit related to pension and other postretirement benefits	79	61	137	99
Foreign currency translation adjustments	(872)	461	(563)	903
Unrealized gains on available-for-sale securities:
Unrealized holding gains		1	2	1
Net amount reclassified to earnings
Net change in unrealized gains on available-for-sale securities		1	2	1
Unrecognized losses on derivatives (N):
Net change from periodic revaluations	136	109	52	(79)
Net amount reclassified to earnings	(2)	42	(1)	82
Net change in unrecognized losses on derivatives	134	151	51	3
Total Other comprehensive (loss) income, net of tax	(659)	674	(373)	1,006
Comprehensive (loss) income	(678)	1,051	(293)	1,749
Alcoa
Net (loss) income	(2)	322	92	630
Other comprehensive (loss) income, net of tax:
Change in unrecognized net actuarial loss and prior service cost/benefit related to pension and other postretirement benefits	75	59	131	96
Foreign currency translation adjustments	(685)	354	(441)	722
Unrealized gains on available-for-sale securities:
Unrealized holding gains		1	2	1
Net amount reclassified to earnings
Net change in unrealized gains on available-for-sale securities		1	2	1
Unrecognized losses on derivatives (N):
Net change from periodic revaluations	140	104	58	(84)
Net amount reclassified to earnings	(2)	42	(1)	82
Net change in unrecognized losses on derivatives	138	146	57	(2)
Total Other comprehensive (loss) income, net of tax	(472)	560	(251)	817
Comprehensive (loss) income	(474)	882	(159)	1,447
Noncontrolling Interest
Net (loss) income	(17)	55	(12)	113
Other comprehensive (loss) income, net of tax:
Change in unrecognized net actuarial loss and prior service cost/benefit related to pension and other postretirement benefits	4	2	6	3
Foreign currency translation adjustments	(187)	107	(122)	181
Unrealized gains on available-for-sale securities:
Net amount reclassified to earnings
Unrecognized losses on derivatives (N):
Net change from periodic revaluations	(4)	5	(6)	5
Net change in unrecognized losses on derivatives	(4)	5	(6)	5
Total Other comprehensive (loss) income, net of tax	(187)	114	(122)	189
Comprehensive (loss) income	$ (204)	$ 169	$ (134)	$ 302