Consolidated Statements Of Income - USD ($) $ in Millions	12 Months Ended
	Dec. 28, 2018	Dec. 29, 2017	Dec. 30, 2016
Income Statement [Abstract]
Revenues	$ 10,194	$ 10,170	$ 7,043
Cost of revenues	8,690	8,738	6,103
Selling, general and administrative expenses	729	737	422
Bad debt expense	0	10	3
Acquisition, integration and restructuring costs	37	139	104
Asset impairment charges	7	0	4
Equity earnings of non-consolidated subsidiaries	(18)	(13)	(10)
Operating income	749	559	417
Non-operating expense:
Interest expense, net	(138)	(140)	(86)
Other expense, net	(1)	(26)	(13)
Income before income taxes	610	393	318
Income tax expense	(28)	(29)	(72)
Net income	582	364	246
Less: net income (loss) attributable to non-controlling interest	1	(2)	2
Net income attributable to Leidos common stockholders	$ 581	$ 366	$ 244
Earnings per share:
Basic (usd per share)	$ 3.85	$ 2.41	$ 2.39
Diluted (usd per share)	$ 3.80	$ 2.38	$ 2.35