Business Segments (Schedule of segment reporting information by segment) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 03, 2020	Jun. 28, 2019	Jul. 03, 2020	Jun. 28, 2019
Segment Reporting Information [Line Items]
Revenues	$ 2,914	$ 2,728	$ 5,803	$ 5,305
Operating income (loss)	249	210	441	402
Operating Segments | Defense Solutions
Segment Reporting Information [Line Items]
Revenues	1,757	1,560	3,462	3,051
Operating income (loss)	119	113	214	217
Operating Segments | Civil
Segment Reporting Information [Line Items]
Revenues	758	667	1,412	1,290
Operating income (loss)	78	56	137	114
Operating Segments | Health
Segment Reporting Information [Line Items]
Revenues	399	501	929	964
Operating income (loss)	1	61	74	106
Corporate
Segment Reporting Information [Line Items]
Operating income (loss)	$ 51	$ (20)	$ 16	$ (35)