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Acquisitions and Divestitures - 2018 Divestitures (Details) $ in Millions		12 Months Ended
	Dec. 31, 2018 USD ($) employee	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Business Acquisition [Line Items]
Gain (loss) on disposition of business		$ (8)	$ (63)	$ (43)
Eger
Business Acquisition [Line Items]
Consideration	$ 2			2
Gain (loss) on disposition of business				(43)
Number of employees \| employee	180
Engineered Structures \| Eger
Business Acquisition [Line Items]
Sales				$ 32