Carrying amount as of the balance sheet date of obligations due all related parties. For classified balance sheets, represents the current portion of such liabilities (due within one year or within the normal operating cycle if longer).

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+ Details

- Definition

Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

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+ Details

Transactions with Related Parties - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Related Party Transaction [Line Items]
Net sales to related parties	$ 341	$ 91	$ 636	$ 442
Accounts payable to related parties	144		144		$ 105
PRO-TEC Coating Company
Related Party Transaction [Line Items]
Accounts payable to related parties	143		143		86
Other equity investees
Related Party Transaction [Line Items]
Accounts payable to related parties	1		1		$ 19
Outside processing services
Related Party Transaction [Line Items]
Purchases from related parties	6	10	26	38
Taconite pellets
Related Party Transaction [Line Items]
Purchases from related parties	$ 30	$ 16	$ 54	$ 34