Business Acquisition (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2020	Dec. 28, 2019
Business Acquisition [Line Items]
Business Acquisition, Description of Acquired Entity	software company that offered a patient referral management solution to clients within the health care industry	consulting company specializing in providing cybersecurity solutions to clients in the health care industry		AbleVets is a health IT engineering and consulting company specializing in cybersecurity, cloud and system development solutions for federal organizations.
Business Combination, Reason for Business Combination	We believe this acquisition enhanced our portfolio of offerings on our HealtheIntent platform	We believe this acquisition enhanced our resource capabilities and growth opportunities for our cybersecurity solution offerings		We believe this acquisition enhanced our resource capabilities and growth opportunities within our federal business.
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				8 years
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				8 years
Business Acquisition, Effective Date of Acquisition	Oct. 19, 2020	Apr. 01, 2020		Oct. 25, 2019
Business Acquisition, Name of Acquired Entity				AbleVets, LLC
Business Acquisition, Description of Acquired Entity	software company that offered a patient referral management solution to clients within the health care industry	consulting company specializing in providing cybersecurity solutions to clients in the health care industry		AbleVets is a health IT engineering and consulting company specializing in cybersecurity, cloud and system development solutions for federal organizations.
Business Combination, Reason for Business Combination	We believe this acquisition enhanced our portfolio of offerings on our HealtheIntent platform	We believe this acquisition enhanced our resource capabilities and growth opportunities for our cybersecurity solution offerings		We believe this acquisition enhanced our resource capabilities and growth opportunities within our federal business.
Business Combination, Consideration Transferred	$ 15	$ 34		$ 76
2020 Acquisitions [Member]
Business Acquisition [Line Items]
Business Acquisition, Goodwill, Expected Tax Deductible Amount	4		$ 4
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			8 years
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			8 years
Business Acquisition, Goodwill, Expected Tax Deductible Amount	$ 4		$ 4

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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With respect to a business combination completed during the period, this element provides a description of the business, other than the name, which may include the industry, size, products and other important information.

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Date when the acquirer obtains control of the acquiree, in CCYY-MM-DD format.

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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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This element represents a description of the primary reason for the business combination which may consist of general categories such as top-line growth, synergistic benefits, market share, and diversification and the more detailed factors that might apply.

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