Statement of Consolidated Comprehensive Income (Loss) (unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Net income (loss)	$ 11	$ 255
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	33	107
Foreign currency translation adjustments	410	(1,207)
Net change in unrealized gains on available-for-sale securities	1	2
Net change in unrecognized losses on cash flow hedges	(82)	(64)
Total Other comprehensive income (loss), net of tax	362	(1,162)
Comprehensive income (loss)	373	(907)
Alcoa [Member]
Net income (loss)	16	195
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	32	105
Foreign currency translation adjustments	303	(957)
Net change in unrealized gains on available-for-sale securities	1	2
Net change in unrecognized losses on cash flow hedges	(80)	(64)
Total Other comprehensive income (loss), net of tax	256	(914)
Comprehensive income (loss)	272	(719)
Noncontrolling Interests [Member]
Net income (loss)	(5)	60
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
Foreign currency translation adjustments	107	(250)
Net change in unrecognized losses on cash flow hedges	(2)
Total Other comprehensive income (loss), net of tax	106	(248)
Comprehensive income (loss)	$ 101	$ (188)