Arconic Inc Separation Transaction and Discontinued Operations - Carrying Amount of Major Classes of Assets and Liabilities (Details) - Arconic Corporation - Discontinued Operations, Disposed of by Means Other than Sale $ in Millions	Dec. 31, 2019 USD ($)
Total assets of discontinued operations
Cash and cash equivalents	$ 71
Receivables from customers	385
Other receivables	135
Inventories	822
Prepaid expenses and other current assets	29
Current assets of discontinued operations	1,442
Properties, plants, and equipment, net	2,834
Goodwill	426
Intangibles, net	60
Deferred income taxes	383
Other noncurrent assets	196
Noncurrent assets of discontinued operations	3,899
Total assets of discontinued operations	5,341
Total liabilities of discontinued operations:
Accounts payable, trade	1,067
Accrued compensation and retirement costs	147
Taxes, including income taxes	22
Other current liabilities	188
Current liabilities of discontinued operations	1,424
Accrued pension benefits	1,429
Accrued other postretirement benefits	514
Other noncurrent liabilities and deferred credits	315
Noncurrent liabilities of discontinued operations	2,258
Total liabilities of discontinued operations	$ 3,682