Basis of Presentation (Unaudited) Sale of our IT and mission support services business (Details 1) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Mar. 31, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jan. 30, 2021
Accounting Policies [Abstract]
Sale of our IT and mission support services business					$ 3,400
Pre-tax gain on sale of business	$ 2,000		$ 2,000
Pretax profit of the IT and mission support services business		$ 69	20	$ 180
Sales for the IT and mission support services business		$ 602	$ 162	$ 1,700

Pre-tax gain on sale of business

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- Definition

Amount of consideration received or receivable for the disposal of assets and liabilities, including discontinued operation.

+ References

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Amount of revenue attributable to disposal group, including, but not limited to, discontinued operation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5B
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109222650&loc=SL51721673-107760

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
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-Section 50
-Paragraph 7
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Amount before tax of income (loss) from an individually significant component disposed of or held-for-sale attributable to parent. Excludes discontinued operations.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 3A
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-URI http://asc.fasb.org/extlink&oid=109226691&loc=SL51724579-110230

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