Statement of Consolidated Comprehensive (Loss) Income (unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Net income	$ 186	$ 106	$ 375	$ 568
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	(463)	120	(363)	226
Foreign currency translation adjustments	202	(1,188)	689	(2,166)
Net change in unrealized losses/gains on available-for-sale securities		(2)	4	(2)
Net change in unrecognized gains/losses on cash flow hedges	(348)	215	(567)	581
Total Other comprehensive (loss) income, net of tax	(609)	(855)	(237)	(1,361)
Comprehensive (loss) income	(423)	(749)	138	(793)
Arconic [Member]
Net income	166	44	317	379
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	(462)	111	(365)	212
Foreign currency translation adjustments	157	(889)	505	(1,649)
Net change in unrealized losses/gains on available-for-sale securities		(2)	4	(2)
Net change in unrecognized gains/losses on cash flow hedges	(338)	214	(571)	584
Total Other comprehensive (loss) income, net of tax	(643)	(566)	(427)	(855)
Comprehensive (loss) income	(477)	(522)	(110)	(476)
Noncontrolling Interests [Member]
Net income	20	62	58	189
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	(1)	9	2	14
Foreign currency translation adjustments	45	(299)	184	(517)
Net change in unrecognized gains/losses on cash flow hedges	(10)	1	4	(3)
Total Other comprehensive (loss) income, net of tax	34	(289)	190	(506)
Comprehensive (loss) income	$ 54	$ (227)	$ 248	$ (317)