Disposition of IT and Mission Support Services (Details 5) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 07, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Group
Accounts receivable, net	$ 110
Unbilled receivables, net	269
Other current assets	9
Property, plant and equipment	14
Operating lease right-of-use assets	38
Goodwill	1,195
Total assets of disposal group held for sale	1,635
Trade accounts payable	(99)
Accrued employee compensation	(59)
Advance payments and billings in excess of costs incurred	(31)
Other current liabilities	(42)
Non-current operating lease liabilities	27
Total liabilities of disposal group held for sale	(258)
Income (Loss) from Individually Significant Component Disposed of or Held-for-sale, Excluding Discontinued Operations, Attributable to Parent, before Income Tax	$ 247	$ 245	$ 288
Disposal Group, Including Discontinued Operation, Consideration				$ 3,400