Cleveland-Cliffs Inc. Quarterly report [Sections 13 or 15(d)]

SUBSEQUENT EVENTS (Details)

v3.25.3

SUBSEQUENT EVENTS (Details) - USD ($) $ in Millions			9 Months Ended
SUBSEQUENT EVENTS (Details) - USD ($) $ in Millions	Oct. 10, 2025	Oct. 03, 2025	Sep. 30, 2025	Sep. 30, 2024	Sep. 08, 2025	Dec. 31, 2024
Subsequent Event [Line Items]
Long-term Debt, Gross			$ 8,135			$ 7,148
Repayments of Long-term Debt			0	$ 845
7.625% 2034 Senior Notes [Member] \| Cleveland-Cliffs Inc.
Subsequent Event [Line Items]
Long-term Debt, Gross			$ 850		$ 850	$ 0
7.625% 2034 Senior Notes [Member] \| Cleveland-Cliffs Inc. \| Debt Instrument, Redemption, Period One
Subsequent Event [Line Items]
Redemption price percentage			100.00%
7.625% 2034 Senior Notes [Member] \| Subsequent Event \| Cleveland-Cliffs Inc.
Subsequent Event [Line Items]
Long-term Debt, Gross	$ 275
7.625% 2034 Senior Notes [Member] \| Subsequent Event \| Cleveland-Cliffs Inc. \| Debt Instrument, Redemption, Period One
Subsequent Event [Line Items]
Redemption price percentage	102.75%
5.875% 2027 Senior Notes, 7.000% 2027 Senior Notes, and 7.000% 2027 AK Senior Notes \| Senior notes \| Subsequent Event
Subsequent Event [Line Items]
Repayments of Long-term Debt		$ 685

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

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