Statement of Consolidated Comprehensive Income (unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net income	$ 143	$ 322
Other comprehensive income, net of tax (J):
Change in unrecognized net actuarial loss and prior service cost/benefit related to pension and other postretirement benefits	143	31
Foreign currency translation adjustments	122	67
Net change in unrealized gains on available-for-sale securities	0	(33)
Net change in unrecognized gains/losses on cash flow hedges	(7)	5
Total Other comprehensive income, net of tax	258	70
Comprehensive income	401	392
Arconic
Net income	143	322
Other comprehensive income, net of tax (J):
Change in unrecognized net actuarial loss and prior service cost/benefit related to pension and other postretirement benefits	143	31
Foreign currency translation adjustments	122	67
Net change in unrealized gains on available-for-sale securities	0	(33)
Net change in unrecognized gains/losses on cash flow hedges	(7)	5
Total Other comprehensive income, net of tax	258	70
Comprehensive income	401	392
Noncontrolling Interests
Net income	0	0
Other comprehensive 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
Foreign currency translation adjustments	0	0
Net change in unrealized gains on available-for-sale securities	0	0
Net change in unrecognized gains/losses on cash flow hedges	0	0
Total Other comprehensive income, net of tax	0	0
Comprehensive income	$ 0	$ 0