Revenues (Disaggregation of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 04, 2025	Jun. 28, 2024	Jul. 04, 2025	Jun. 28, 2024
Disaggregation of Revenue [Line Items]
Revenues	$ 4,233	$ 4,107	$ 8,461	$ 8,058
United States
Disaggregation of Revenue [Line Items]
Revenues	3,893	3,749	7,774	7,384
International
Disaggregation of Revenue [Line Items]
Revenues	340	358	687	674
Cost-reimbursement and fixed-price-incentive-fee
Disaggregation of Revenue [Line Items]
Revenues	1,851	1,802	3,739	3,581
Firm-fixed-price
Disaggregation of Revenue [Line Items]
Revenues	1,827	1,738	3,596	3,378
Time-and-materials and fixed-price-level-of-effort
Disaggregation of Revenue [Line Items]
Revenues	555	567	1,126	1,099
National Security & Digital
Disaggregation of Revenue [Line Items]
Revenues	1,857	1,795	3,724	3,574
National Security & Digital \| United States
Disaggregation of Revenue [Line Items]
Revenues	1,849	1,788	3,708	3,558
National Security & Digital \| International
Disaggregation of Revenue [Line Items]
Revenues	8	7	16	16
National Security & Digital \| Cost-reimbursement and fixed-price-incentive-fee
Disaggregation of Revenue [Line Items]
Revenues	1,007	948	2,020	1,894
National Security & Digital \| Firm-fixed-price
Disaggregation of Revenue [Line Items]
Revenues	514	494	1,011	986
National Security & Digital \| Time-and-materials and fixed-price-level-of-effort
Disaggregation of Revenue [Line Items]
Revenues	336	353	693	694
Health & Civil
Disaggregation of Revenue [Line Items]
Revenues	1,267	1,257	2,553	2,447
Health & Civil \| United States
Disaggregation of Revenue [Line Items]
Revenues	1,265	1,255	2,550	2,444
Health & Civil \| International
Disaggregation of Revenue [Line Items]
Revenues	2	2	3	3
Health & Civil \| Cost-reimbursement and fixed-price-incentive-fee
Disaggregation of Revenue [Line Items]
Revenues	430	451	901	898
Health & Civil \| Firm-fixed-price
Disaggregation of Revenue [Line Items]
Revenues	787	749	1,546	1,439
Health & Civil \| Time-and-materials and fixed-price-level-of-effort
Disaggregation of Revenue [Line Items]
Revenues	50	57	106	110
Commercial & International
Disaggregation of Revenue [Line Items]
Revenues	566	560	1,133	1,068
Commercial & International \| United States
Disaggregation of Revenue [Line Items]
Revenues	247	227	485	435
Commercial & International \| International
Disaggregation of Revenue [Line Items]
Revenues	319	333	648	633
Commercial & International \| Cost-reimbursement and fixed-price-incentive-fee
Disaggregation of Revenue [Line Items]
Revenues	90	90	185	175
Commercial & International \| Firm-fixed-price
Disaggregation of Revenue [Line Items]
Revenues	345	352	704	671
Commercial & International \| Time-and-materials and fixed-price-level-of-effort
Disaggregation of Revenue [Line Items]
Revenues	131	118	244	222
Defense Systems
Disaggregation of Revenue [Line Items]
Revenues	543	495	1,051	969
Defense Systems \| United States
Disaggregation of Revenue [Line Items]
Revenues	532	479	1,031	947
Defense Systems \| International
Disaggregation of Revenue [Line Items]
Revenues	11	16	20	22
Defense Systems \| Cost-reimbursement and fixed-price-incentive-fee
Disaggregation of Revenue [Line Items]
Revenues	324	313	633	614
Defense Systems \| Firm-fixed-price
Disaggregation of Revenue [Line Items]
Revenues	181	143	335	282
Defense Systems \| Time-and-materials and fixed-price-level-of-effort
Disaggregation of Revenue [Line Items]
Revenues	38	39	83	73
DoD and U.S. Intelligence Community
Disaggregation of Revenue [Line Items]
Revenues	2,065	1,947	4,124	3,860
DoD and U.S. Intelligence Community \| National Security & Digital
Disaggregation of Revenue [Line Items]
Revenues	1,324	1,247	2,650	2,468
DoD and U.S. Intelligence Community \| Health & Civil
Disaggregation of Revenue [Line Items]
Revenues	253	255	522	512
DoD and U.S. Intelligence Community \| Commercial & International
Disaggregation of Revenue [Line Items]
Revenues	2	4	12	14
DoD and U.S. Intelligence Community \| Defense Systems
Disaggregation of Revenue [Line Items]
Revenues	486	441	940	866
Other U.S. government agencies
Disaggregation of Revenue [Line Items]
Revenues	1,624	1,611	3,260	3,148
Other U.S. government agencies \| National Security & Digital
Disaggregation of Revenue [Line Items]
Revenues	507	520	1,023	1,045
Other U.S. government agencies \| Health & Civil
Disaggregation of Revenue [Line Items]
Revenues	995	986	1,994	1,903
Other U.S. government agencies \| Commercial & International
Disaggregation of Revenue [Line Items]
Revenues	99	81	196	154
Other U.S. government agencies \| Defense Systems
Disaggregation of Revenue [Line Items]
Revenues	23	24	47	46
Commercial and non-U.S. customers
Disaggregation of Revenue [Line Items]
Revenues	544	549	1,077	1,050
Commercial and non-U.S. customers \| National Security & Digital
Disaggregation of Revenue [Line Items]
Revenues	26	28	51	61
Commercial and non-U.S. customers \| Health & Civil
Disaggregation of Revenue [Line Items]
Revenues	19	16	37	32
Commercial and non-U.S. customers \| Commercial & International
Disaggregation of Revenue [Line Items]
Revenues	465	475	925	900
Commercial and non-U.S. customers \| Defense Systems
Disaggregation of Revenue [Line Items]
Revenues	$ 34	$ 30	$ 64	$ 57