Statement of Consolidated Comprehensive Income (Loss) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Net income (loss)	$ 129	$ (148)	$ (68)	$ 22
Other comprehensive income (loss), net of tax (C):
Change in unrecognized net actuarial loss and prior service cost/benefit related to pension and other postretirement benefits	15	63	92	159
Foreign currency translation adjustments	200	(852)	536	(952)
Net change in unrealized gains on available-for-sale securities	1	(3)	1	(2)
Net change in unrecognized losses on cash flow hedges	(31)	69	3	184
Total Other comprehensive income (loss), net of tax	185	(723)	632	(611)
Comprehensive income (loss)	314	(871)	564	(589)
Alcoa [Member]
Net income (loss)	138	(119)	(40)	30
Other comprehensive income (loss), net of tax (C):
Change in unrecognized net actuarial loss and prior service cost/benefit related to pension and other postretirement benefits	14	61	91	156
Foreign currency translation adjustments	141	(603)	390	(719)
Net change in unrealized gains on available-for-sale securities	1	(3)	1	(2)
Net change in unrecognized losses on cash flow hedges	(23)	71	9	184
Total Other comprehensive income (loss), net of tax	133	(474)	491	(381)
Comprehensive income (loss)	271	(593)	451	(351)
Noncontrolling Interests [Member]
Net income (loss)	(9)	(29)	(28)	(8)
Other comprehensive income (loss), net of tax (C):
Change in unrecognized net actuarial loss and prior service cost/benefit related to pension and other postretirement benefits	1	2	1	3
Foreign currency translation adjustments	59	(249)	146	(233)
Net change in unrealized gains on available-for-sale securities	0	0	0	0
Net change in unrecognized losses on cash flow hedges	(8)	(2)	(6)	0
Total Other comprehensive income (loss), net of tax	52	(249)	141	(230)
Comprehensive income (loss)	$ 43	$ (278)	$ 113	$ (238)