Number of persons employed by the Entity

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- Definition

Decrease In Income Before Income Taxes From Changes In Contract Estimates

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Significant Accounting Policies [Line Items]

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Sum of the carrying values as of the balance sheet date of obligations incurred through that date and due within one year (or the operating cycle, if longer), including liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received, taxes, interest, rent and utilities, accrued salaries and bonuses, payroll taxes and fringe benefits.

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- Definition

Amount of revenue recognized from performance obligation satisfied or partially satisfied in previous reporting periods. Includes, but is not limited to, change in transaction price.

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The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

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- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

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Amount of cash and cash equivalents restricted as to withdrawal or usage. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Basis of Presentation and Summary of Significant Accounting Policies (Narrative) (Details) employee in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 27, 2024 USD ($) employee	Sep. 29, 2023 USD ($)	Sep. 27, 2024 USD ($) employee segment	Sep. 29, 2023 USD ($)	Dec. 29, 2023 USD ($)
Significant Accounting Policies [Line Items]
Number of employees in global workforce \| employee	48		48
Number of reportable segments \| segment			4
Decrease in income before income taxes from changes in contract estimates	$ 28	$ 24	$ 107	$ 62
Revenue recognized for performance obligation satisfied in the previous periods	78	$ 13	12	$ 14
Accounts payable and accrued liabilities	2,287		2,287		$ 2,277
Restricted cash balances	141		141		151
Cash and Cash Equivalents
Significant Accounting Policies [Line Items]
Accounts payable and accrued liabilities	$ 91		91		$ 136
UNITED KINGDOM
Significant Accounting Policies [Line Items]
Decrease in income before income taxes from changes in contract estimates			$ (41)
Leidos, Inc.
Significant Accounting Policies [Line Items]
Controlling ownership interest (as percent)	100.00%		100.00%