For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Segment Information - Narrative (Details) $ in Millions		9 Months Ended
Segment Information - Narrative (Details) $ in Millions	Jan. 01, 2020 USD ($)	Sep. 30, 2021 USD ($) segment	Sep. 30, 2020	Dec. 31, 2020 USD ($)	Mar. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Number of reportable segments \| segment		4
Goodwill		$ 4,077		$ 4,102
Goodwill, impairment loss	$ 0
Revenue Benchmark \| Customer Concentration Risk \| Aerospace
Segment Reporting Information [Line Items]
Concentration risk, percentage		60.00%	70.00%
Revenue Benchmark \| Customer Concentration Risk \| Aerospace \| General Electric Company \| Engine Products
Segment Reporting Information [Line Items]
Concentration risk, percentage		13.00%	11.00%
Engineered Structures
Segment Reporting Information [Line Items]
Goodwill reallocated, increase (decrease)	17
Percentage of fair value in excess of carrying amount					15.00%	60.00%
Engine Products
Segment Reporting Information [Line Items]
Goodwill reallocated, increase (decrease)	$ (17)