Accumulated Other Comprehensive Loss (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2016

Dec. 31, 2015

Equity [Abstract]

Summary of Changes in Accumulated Other Comprehensive (Loss) Income by Component

The following table details the activity of the three components that comprise Accumulated other comprehensive loss for both Alcoa Corporation and noncontrolling interest:

	Alcoa Corporation						Noncontrolling Interest
	Third quarter ended September 30,						Third quarter ended September 30,
	2016			2015			2016			2015
Pension and other postretirement benefits (L)
Balance at beginning of period	$	(353	)	$	(383	)	$	(53	)	$	(59	)
Establishment of defined benefit plans		(2,704	)		—			—			—
Other comprehensive income (loss):
Unrecognized net actuarial loss and prior service cost/benefit		(22	)		49			(1	)		10
Tax benefit (expense)		17			(11	)		—			(1	)
Total Other comprehensive (loss) income before reclassifications, net of tax		(5	)		38			(1	)		9
Amortization of net actuarial loss and prior service cost/benefit(1)		38			5			1			—
Tax expense(2)		(13	)		(1	)		(1	)		—
Total amount reclassified from Accumulated other comprehensive loss, net of tax(6)		25			4			—			—
Total Other comprehensive income (loss)		20			42			(1	)		9
Balance at end of period	$	(3,037	)	$	(341	)	$	(54	)	$	(50	)
Foreign currency translation
Balance at beginning of period	$	(1,437	)	$	(1,282	)	$	(640	)	$	(569	)
Other comprehensive income (loss)(3)		32			(743	)		45			(298	)
Balance at end of period	$	(1,405	)	$	(2,025	)	$	(595	)	$	(867	)
Cash flow hedges (M)
Balance at beginning of period	$	334		$	167		$	11		$	(6	)
Other comprehensive (loss) income:
Net change from periodic revaluations		(434	)		302			20			1
Tax benefit (expense)		95			(105	)		(6	)		—
Total Other comprehensive (loss) income before reclassifications, net of tax		(339	)		197			14			1
Net amount reclassified to earnings:
Aluminum contracts(4)		4			2			—			—
Energy contracts(5)		(50	)		—			(34	)		—
Sub-total		(46	)		2			(34	)		—
Tax benefit(2)		15			—			10			—
Total amount reclassified from Accumulated other comprehensive income (loss), net of tax(6)		(31	)		2			(24	)		—
Total Other comprehensive (loss) income		(370	)		199			(10	)		1
Balance at end of period	$	(36	)	$	366		$	1		$	(5	)

	Alcoa Corporation						Noncontrolling Interest
	Nine months ended September 30,						Nine months ended September 30,
	2016			2015			2016			2015
Pension and other postretirement benefits (L)
Balance at beginning of period	$	(352	)	$	(424	)	$	(56	)	$	(64	)
Establishment of defined benefit plans		(2,704	)		—			—			—
Other comprehensive income:
Unrecognized net actuarial loss and prior service cost/benefit		(44	)		90			—			13
Tax benefit (expense)		25			(21	)		—			(1	)
Total Other comprehensive (loss) income before reclassifications, net of tax		(19	)		69			—			12
Amortization of net actuarial loss and prior service cost/benefit(1)		58			21			3			4
Tax expense(2)		(20	)		(7	)		(1	)		(2	)
Total amount reclassified from Accumulated other comprehensive loss, net of tax(6)		38			14			2			2
Total Other comprehensive income		19			83			2			14
Balance at end of period	$	(3,037	)	$	(341	)	$	(54	)	$	(50	)
Foreign currency translation
Balance at beginning of period	$	(1,851	)	$	(668	)	$	(779	)	$	(351	)
Other comprehensive income (loss)(3)		446			(1,357	)		184			(516	)
Balance at end of period	$	(1,405	)	$	(2,025	)	$	(595	)	$	(867	)
Cash flow hedges (M)
Balance at beginning of period	$	603		$	(224	)	$	(3	)	$	(2	)
Other comprehensive (loss) income:
Net change from periodic revaluations		(779	)		813			35			(4	)
Tax benefit (expense)		170			(242	)		(10	)		1
Total Other comprehensive (loss) income before reclassifications, net of tax		(609	)		571			25			(3	)
Net amount reclassified to earnings:
Aluminum contracts(4)		(1	)		25			—			—
Energy contracts(5)		(50	)		—			(34	)		—
Interest rate contracts(5)		7			—			5			—
Sub-total		(44	)		25			(29	)		—
Tax benefit (expense)(2)		14			(6	)		8			—
Total amount reclassified from Accumulated other comprehensive income (loss), net of tax(6)		(30	)		19			(21	)		—
Total Other comprehensive (loss) income		(639	)		590			4			(3	)
Balance at end of period	$	(36	)	$	366		$	1		$	(5	)

(1) These amounts were included in the computation of net periodic benefit cost for pension and other postretirement benefits (see Note L).

(2) These amounts were included in Provision for income taxes on the accompanying Statement of Combined Operations.

(3) In all periods presented, there were no tax impacts related to rate changes and no amounts were reclassified to earnings.

(4) These amounts were included in Sales on the accompanying Statement of Combined Operations.

(5) These amounts were included in Other income, net on the accompanying Statement of Combined Operations.

(6) A positive amount indicates a corresponding charge to earnings and a negative amount indicates a corresponding benefit to earnings. These amounts were reflected on the accompanying Statement of Combined Operations in the line items indicated in footnotes 1 through 5.

The following table details the activity of the three components that comprise Accumulated other comprehensive loss for both Alcoa Corporation and noncontrolling interest:

			Alcoa Corporation									Noncontrolling interest
	Note		2015			2014			2013			2015			2014			2013
Pension and other postretirement benefits		W
Balance at beginning of period				(424	)		(373	)		(554	)		(64	)		(51	)		(77	)
Other comprehensive income (loss):
Unrecognized net actuarial loss/gain and prior service cost/benefit				73			(109	)		197			5			(22	)		28
Tax (expense) benefit				(18	)		35			(54	)		(1	)		7			(9	)
Total Other comprehensive income (loss) before reclassifications, net of tax				55			(74	)		143			4			(15	)		19
Amortization of net actuarial loss/gain and prior service cost/benefit(1)				26			35			58			6			3			11
Tax expense(2)				(9	)		(12	)		(20	)		(2	)		(1	)		(4	)
Total amount reclassified from Accumulated other comprehensive loss, net of tax(5)				17			23			38			4			2			7
Total Other comprehensive income (loss)				72			(51	)		181			8			(13	)		26
Balance at end of period				(352	)		(424	)		(373	)		(56	)		(64	)		(51	)
Foreign currency translation
Balance at beginning of period				(668	)		20			812			(351	)		(115	)		252
Other comprehensive loss(3)				(1,183	)		(688	)		(792	)		(428	)		(236	)		(367	)
Balance at end of period				(1,851	)		(668	)		20			(779	)		(351	)		(115	)
Cash flow hedges		X
Balance at beginning of period				(224	)		(304	)		(485	)		(2	)		(2	)		(5	)
Other comprehensive income (loss):
Net change from periodic revaluations				1,155			78			197			(1	)		—			4
Tax expense				(344	)		(20	)		(40	)		—			—			(1	)
Total Other comprehensive income (loss) before reclassifications, net of tax				811			58			157			(1	)		—			3
Net amount reclassified to earnings:
Aluminum contracts(4)				21			26			30			—			—			—
Tax expense(2)				(5	)		(4	)		(6	)		—			—			—
Total amount reclassified from Accumulated other comprehensive loss, net of tax(5)				16			22			24			—			—			—
Total Other comprehensive income (loss)				827			80			181			(1	)		—			3
Balance at end of period				603			(224	)		(304	)		(3	)		(2	)		(2	)

(1) These amounts were included in the computation of net periodic benefit cost for pension and other postretirement benefits (see Note W).

(2) These amounts were included in Provision for income taxes on the accompanying Statement of Combined Operations.

(3) In all periods presented, there were no tax impacts related to rate changes and no amounts were reclassified to earnings.

(4) These amounts were included in Sales on the accompanying Statement of Combined Operations.

(5) A positive amount indicates a corresponding charge to earnings and a negative amount indicates a corresponding benefit to earnings. These amounts were reflected on the accompanying Statement of Combined Operations in the line items indicated in footnotes 1 through 4.