Consolidation (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023
Current assets:
Cash and cash equivalents	$ 886	$ 1,309	$ 1,041
Inventories	2,755	2,515
Prepaid expenses and other current assets	148	152
Total current assets	6,063	5,943
Property, plant and equipment, net	5,849	5,741
Goodwill	1,073	1,074
Deferred income tax assets	146	143
Total assets	14,859	14,628
Current liabilities:
Accrued expenses and other current liabilities	579	627
Total current liabilities	5,013	4,835
Accrued postretirement benefits	537	559
Other long-term liabilities	293	305
Total liabilities	10,946	10,818
Primary Beneficiary
Current assets:
Cash and cash equivalents	3	4
Accounts receivable, net	7	10
Inventories	135	142
Prepaid expenses and other current assets	8	8
Total current assets	153	164
Property, plant and equipment, net	105	104
Goodwill	12	12
Deferred income tax assets	36	36
Other long-term assets	4	4
Total assets	310	320
Current liabilities:
Accounts payable	148	135
Accrued expenses and other current liabilities	29	34
Total current liabilities	177	169
Accrued postretirement benefits	104	121
Other long-term liabilities	2	2
Total liabilities	$ 283	$ 292
Logan Aluminum Inc.
Current liabilities:
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage	40.00%