Revenues (Disaggregation of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended
Apr. 04, 2025	Mar. 29, 2024
Disaggregation of Revenue [Line Items]
Revenues	$ 4,228	$ 3,951
United States
Disaggregation of Revenue [Line Items]
Revenues	3,881	3,635
International
Disaggregation of Revenue [Line Items]
Revenues	347	316
Cost-reimbursement and fixed-price-incentive-fee
Disaggregation of Revenue [Line Items]
Revenues	1,888	1,779
Firm-fixed-price
Disaggregation of Revenue [Line Items]
Revenues	1,769	1,640
Time-and-materials and fixed-price-level-of-effort
Disaggregation of Revenue [Line Items]
Revenues	571	532
National Security & Digital
Disaggregation of Revenue [Line Items]
Revenues	1,867	1,779
National Security & Digital \| United States
Disaggregation of Revenue [Line Items]
Revenues	1,859	1,770
National Security & Digital \| International
Disaggregation of Revenue [Line Items]
Revenues	8	9
National Security & Digital \| Cost-reimbursement and fixed-price-incentive-fee
Disaggregation of Revenue [Line Items]
Revenues	1,013	946
National Security & Digital \| Firm-fixed-price
Disaggregation of Revenue [Line Items]
Revenues	497	492
National Security & Digital \| Time-and-materials and fixed-price-level-of-effort
Disaggregation of Revenue [Line Items]
Revenues	357	341
Health & Civil
Disaggregation of Revenue [Line Items]
Revenues	1,286	1,190
Health & Civil \| United States
Disaggregation of Revenue [Line Items]
Revenues	1,285	1,189
Health & Civil \| International
Disaggregation of Revenue [Line Items]
Revenues	1	1
Health & Civil \| Cost-reimbursement and fixed-price-incentive-fee
Disaggregation of Revenue [Line Items]
Revenues	471	447
Health & Civil \| Firm-fixed-price
Disaggregation of Revenue [Line Items]
Revenues	759	690
Health & Civil \| Time-and-materials and fixed-price-level-of-effort
Disaggregation of Revenue [Line Items]
Revenues	56	53
Commercial & International
Disaggregation of Revenue [Line Items]
Revenues	567	508
Commercial & International \| United States
Disaggregation of Revenue [Line Items]
Revenues	238	208
Commercial & International \| International
Disaggregation of Revenue [Line Items]
Revenues	329	300
Commercial & International \| Cost-reimbursement and fixed-price-incentive-fee
Disaggregation of Revenue [Line Items]
Revenues	95	85
Commercial & International \| Firm-fixed-price
Disaggregation of Revenue [Line Items]
Revenues	359	319
Commercial & International \| Time-and-materials and fixed-price-level-of-effort
Disaggregation of Revenue [Line Items]
Revenues	113	104
Defense Systems
Disaggregation of Revenue [Line Items]
Revenues	508	474
Defense Systems \| United States
Disaggregation of Revenue [Line Items]
Revenues	499	468
Defense Systems \| International
Disaggregation of Revenue [Line Items]
Revenues	9	6
Defense Systems \| Cost-reimbursement and fixed-price-incentive-fee
Disaggregation of Revenue [Line Items]
Revenues	309	301
Defense Systems \| Firm-fixed-price
Disaggregation of Revenue [Line Items]
Revenues	154	139
Defense Systems \| Time-and-materials and fixed-price-level-of-effort
Disaggregation of Revenue [Line Items]
Revenues	45	34
DoD and U.S. Intelligence Community
Disaggregation of Revenue [Line Items]
Revenues	2,059	1,913
DoD and U.S. Intelligence Community \| National Security & Digital
Disaggregation of Revenue [Line Items]
Revenues	1,326	1,221
DoD and U.S. Intelligence Community \| Health & Civil
Disaggregation of Revenue [Line Items]
Revenues	269	257
DoD and U.S. Intelligence Community \| Commercial & International
Disaggregation of Revenue [Line Items]
Revenues	10	10
DoD and U.S. Intelligence Community \| Defense Systems
Disaggregation of Revenue [Line Items]
Revenues	454	425
Other U.S. government agencies
Disaggregation of Revenue [Line Items]
Revenues	1,636	1,537
Other U.S. government agencies \| National Security & Digital
Disaggregation of Revenue [Line Items]
Revenues	516	525
Other U.S. government agencies \| Health & Civil
Disaggregation of Revenue [Line Items]
Revenues	999	917
Other U.S. government agencies \| Commercial & International
Disaggregation of Revenue [Line Items]
Revenues	97	73
Other U.S. government agencies \| Defense Systems
Disaggregation of Revenue [Line Items]
Revenues	24	22
Commercial and non-U.S. customers
Disaggregation of Revenue [Line Items]
Revenues	533	501
Commercial and non-U.S. customers \| National Security & Digital
Disaggregation of Revenue [Line Items]
Revenues	25	33
Commercial and non-U.S. customers \| Health & Civil
Disaggregation of Revenue [Line Items]
Revenues	18	16
Commercial and non-U.S. customers \| Commercial & International
Disaggregation of Revenue [Line Items]
Revenues	460	425
Commercial and non-U.S. customers \| Defense Systems
Disaggregation of Revenue [Line Items]
Revenues	$ 30	$ 27