Statement of Consolidated Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash from Operations
Net (loss) income	$ (74)	$ (878)	$ (197)
Adjustments to reconcile net loss to cash from operations:
Depreciation, depletion and amortization	551	1,132	1,280
Deferred income taxes	434	1,125	34
Equity income, net of dividends	0	42	158
Impairment of goodwill (A and E)	719	0	25
Restructuring and other charges	165	257	1,195
Net gain from investing activities—asset sales	(513)	(156)	(74)
Net periodic pension benefit cost	217	304	485
Stock-based compensation	67	86	92
Excess tax benefits from stock-based payment arrangements	0	0	(9)
Other	61	60	(32)
Changes in assets and liabilities, excluding effects of acquisitions, divestitures, and foreign currency translation adjustments:
(Increase) decrease in receivables	(124)	(238)	212
(Increase) in inventories	(192)	(29)	(64)
Decrease (increase) in prepaid expenses and other current assets	11	(76)	46
Increase (decrease) in accounts payable, trade	62	232	(90)
(Decrease) in accrued expenses	(116)	(394)	(437)
(Decrease) increase in taxes, including income taxes	(23)	93	25
Pension contributions	(310)	(290)	(470)
(Increase) in noncurrent assets	(41)	(152)	(370)
(Decrease) in noncurrent liabilities	(193)	(248)	(227)
Cash provided from operations	701	870	1,582
Financing Activities
Net change in short-term borrowings (original maturities of three months or less)	(2)	(3)	(16)
Additions to debt (original maturities greater than three months)	816	1,962	1,901
Payments on debt (original maturities greater than three months)	(1,634)	(2,734)	(2,030)
Proceeds from exercise of employee stock options	50	4	25
Excess tax benefits from stock-based payment arrangements	0	0	9
Dividends paid to shareholders	(162)	(228)	(223)
Distributions to noncontrolling interests	(14)	(226)	(106)
Contributions from noncontrolling interests	0	51	2
Net cash transferred from Alcoa Corporation at separation	0	421	0
Other	(17)	(1)	(3)
Cash used for financing activities	(963)	(754)	(441)
Investing Activities
Capital expenditures	(596)	(1,125)	(1,180)
Acquisitions, net of cash acquired (F and M)	0	10	97
Proceeds from the sale of assets and businesses (M)	(9)	692	112
Additions to investments	(2)	(52)	(134)
Sales of investments (C and M)	890	280	40
Net change in restricted cash	12	14	(20)
Other (C)	245	16	25
Cash provided from (used for) investing activities	540	(165)	(1,060)
Effect of exchange rate changes on cash and cash equivalents	9	(7)	(39)
Net change in cash and cash equivalents	287	(56)	42
Cash and cash equivalents at beginning of year	1,863	1,919	1,877
Cash and cash equivalents at end of year	$ 2,150	$ 1,863	$ 1,919