Statement of Consolidated Comprehensive Income (unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Net income	$ 120	$ 212	$ 263	$ 534
Other comprehensive (loss) income, net of tax (J):
Change in unrecognized net actuarial loss and prior service cost/benefit related to pension and other postretirement benefits	29	48	172	79
Foreign currency translation adjustments	(201)	99	(79)	166
Net change in unrealized gains on available-for-sale securities	(2)	(101)	(2)	(134)
Net change in unrecognized losses/gains on cash flow hedges	4	(2)	(3)	3
Total Other comprehensive (loss) income, net of tax	(170)	44	88	114
Comprehensive (loss) income	(50)	256	351	648
Arconic
Net income	120	212	263	534
Other comprehensive (loss) income, net of tax (J):
Change in unrecognized net actuarial loss and prior service cost/benefit related to pension and other postretirement benefits	29	48	172	79
Foreign currency translation adjustments	(201)	99	(79)	166
Net change in unrealized gains on available-for-sale securities	(2)	(101)	(2)	(134)
Net change in unrecognized losses/gains on cash flow hedges	4	(2)	(3)	3
Total Other comprehensive (loss) income, net of tax	(170)	44	88	114
Comprehensive (loss) income	(50)	256	351	648
Noncontrolling Interests
Net income	0	0	0	0
Other comprehensive (loss) income, net of tax (J):
Change in unrecognized net actuarial loss and prior service cost/benefit related to pension and other postretirement benefits	0	0	0	0
Foreign currency translation adjustments	0	0	0	0
Net change in unrealized gains on available-for-sale securities	0	0	0	0
Net change in unrecognized losses/gains on cash flow hedges	0	0	0	0
Total Other comprehensive (loss) income, net of tax	0	0	0	0
Comprehensive (loss) income	$ 0	$ 0	$ 0	$ 0