EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Numerator:
Net income attributable to equity holders of Constellium	$ 36	$ 76	$ 73	$ 97
Denominator:
Basic - weighted-average ordinary shares outstanding (in shares)	140,820,828	146,271,938	141,665,123	146,534,099
Dilutive effect of non-vested restricted stock units and performance-based restricted stock units (in shares)	1,423,571	2,960,935	1,508,801	3,187,852
Diluted - weighted-average ordinary shares, of restricted stock units and performance-based restricted stock units (in shares)	142,244,399	149,232,873	143,173,924	149,721,951
Basic earnings per share (in USD per share)	$ 0.25	$ 0.52	$ 0.51	$ 0.66
Diluted earnings per share (in USD per share)	$ 0.25	$ 0.51	$ 0.51	$ 0.65
Antidilutive securities excluded from computation of earnings per share (in shares)	0	0	0	0

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ Details

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References

+ Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

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+ Details

CONSTELLIUM SE 10-Q