Statement of Consolidated Comprehensive (Loss) Income (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Net income (loss)	$ 131	$ 44	$ 63	$ 66
Other comprehensive (loss) income, net of tax (C):
Change in unrecognized net actuarial loss and prior service cost/benefit related to pension and other postretirement benefits	122	124	214	283
Foreign currency translation adjustments	(1,000)	(36)	(464)	(988)
Net change in unrealized gains on available-for-sale securities	(1)	1	0	(1)
Net change in unrecognized losses on cash flow hedges	(14)	(49)	(11)	135
Total Other comprehensive (loss) income, net of tax	(893)	40	(261)	(571)
Comprehensive (loss) income	(762)	84	(198)	(505)
Alcoa [Member]
Net income (loss)	149	24	109	54
Other comprehensive (loss) income, net of tax (C):
Change in unrecognized net actuarial loss and prior service cost/benefit related to pension and other postretirement benefits	126	122	217	278
Foreign currency translation adjustments	(774)	(4)	(384)	(723)
Net change in unrealized gains on available-for-sale securities	(1)	1	0	(1)
Net change in unrecognized losses on cash flow hedges	(19)	(50)	(10)	134
Total Other comprehensive (loss) income, net of tax	(668)	69	(177)	(312)
Comprehensive (loss) income	(519)	93	(68)	(258)
Noncontrolling Interests [Member]
Net income (loss)	(18)	20	(46)	12
Other comprehensive (loss) income, net of tax (C):
Change in unrecognized net actuarial loss and prior service cost/benefit related to pension and other postretirement benefits	(4)	2	(3)	5
Foreign currency translation adjustments	(226)	(32)	(80)	(265)
Net change in unrealized gains on available-for-sale securities	0	0	0	0
Net change in unrecognized losses on cash flow hedges	5	1	(1)	1
Total Other comprehensive (loss) income, net of tax	(225)	(29)	(84)	(259)
Comprehensive (loss) income	$ (243)	$ (9)	$ (130)	$ (247)