Summary of Significant Accounting Policies Update - Contracts accounted for under cumulative catch-up method (Details) - Cumulative catch-up method - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
Mar. 31, 2018	Apr. 01, 2017
Use of Estimates
Cumulative Catch-Up Adjustments	$ 40	$ (12)
Change in Accounting Estimate Financial Effect Increase (Decrease) In Income From Continuing Operations Before Income Taxes	40	(12)
Change in Accounting Estimate Financial Effect Increase (Decrease) In Income From Continuing Operations After Income Taxes	$ 30	$ (8)
Change In Accounting Estimate Financial Effect Increase (Decrease) In Earnings Per Share Diluted	$ 0.12	$ (0.03)
Gross favorable adjustments	$ 56	$ 20
Gross unfavorable adjustments	$ 16	32
Gross unfavorable loss adjustments related to Tactical Armoured Patrol Vehicle Program		$ 24

Change in accounting estimate financial effect increase (decrease) in earnings per share diluted.

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Change in accounting estimate financial effect increase (decrease) in income from continuing operations after income taxes.

No definition available.

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Change in accounting estimate financial effect increase (decrease) in income from continuing operations before income taxes.

No definition available.

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The impact of cumulative catch-up profit adjustments on both revenues and segment profit recognized in prior periods.

No definition available.

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The amount of total gross favorable adjustments.

No definition available.

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The amount of total gross unfavorable adjustments.

No definition available.

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Represents the gross unfavorable adjustments of loss related to the Tactical Armoured Patrol Vehicle program.

No definition available.

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No definition available.

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