Inventory (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jul. 01, 2021	Jul. 01, 2021	Dec. 31, 2020
Summary Of Inventories [Abstract]
Raw materials	$ 323.3	$ 323.3	$ 337.3
Work-in-process	913.3	913.3	1,000.6
Finished goods	42.5	42.5	58.1
Product inventory	1,279.1	1,279.1	1,396.0
Capitalized pre-production	26.3	26.3	26.3
Total inventory, net	1,305.4	1,305.4	1,422.3
Inventory Valuation Reserves	52.0	52.0	56.8
Costs Incurred in Anticipation of Contracts	344.5	344.5	$ 351.2
Excess Capacity Costs- B737MAX and A320 Production Schedules	47.5	115.1
Abnormal Costs- COVID19 production suspension	$ 2.4	$ 4.5

Abnormal Costs- COVID19 production suspension

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Costs Incurred in Anticipation of Contracts included in Work-in-process

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Excess Capacity Costs- B737MAX and A320 Production Schedules

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Net Inventory Raw Materials Finished Goods And Work In Process

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Carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of merchandise or goods held by the company that are readily available for sale.

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Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

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Carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of unprocessed items to be consumed in the manufacturing or production process.

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Amount of valuation reserve for inventory.

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Carrying amount, net of reserves and adjustments, as of the balance sheet date of merchandise or goods which are partially completed. This inventory is generally comprised of raw materials, labor and factory overhead costs, which require further materials, labor and overhead to be converted into finished goods, and which generally require the use of estimates to determine percentage complete and pricing.

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Amount, before valuation and last-in first out (LIFO) reserves, of costs capitalized in inventory classified as other, expected to be sold, or consumed within one year or operating cycle, if longer.

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