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Restructuring and Other Charges (Credits) - Activity and Reserve Balances for Restructuring Charges (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2026	Mar. 31, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Restructuring Reserve [Roll Forward]
Reserve balance at beginning of period		$ 1		$ 1
Cash payments				(1)
Restructuring and other charges (credits)	$ 2		$ 0	(91)	$ (4)
Other				94
Reserve balance at end of period	3			3
Disposed by Sale \| Disk Forging Facility
Restructuring Reserve [Roll Forward]
Gain from disposal of business		93		93
Layoff costs
Restructuring Reserve [Roll Forward]
Reserve balance at beginning of period		1		1
Cash payments				0
Restructuring and other charges (credits)				2
Other				0
Reserve balance at end of period	3			3
Other exit costs
Restructuring Reserve [Roll Forward]
Reserve balance at beginning of period		$ 0		0
Cash payments				(1)
Restructuring and other charges (credits)				(93)
Other				94
Reserve balance at end of period	$ 0			$ 0