Summary of Significant Accounting Policies (Net EAC adjustments) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 29, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Change in Accounting Estimate [Line Items]
Operating income									$ 4,774	$ 4,538	$ 4,231
Income from continuing operations attributable to Raytheon Company	$ 879	$ 861	$ 813	$ 775	$ 828	$ 641	$ 790	$ 624	$ 3,342	$ 2,910	$ 2,022
Diluted EPS from continuing operations attributable to Raytheon Company common stockholders	$ 3.16	$ 3.08	$ 2.92	$ 2.77	$ 2.93	$ 2.25	$ 2.78	$ 2.20	$ 11.92	$ 10.15	$ 6.94
Contracts Accounted for under Percentage of Completion [Member]
Change in Accounting Estimate [Line Items]
Operating income									$ 520	$ 492	$ 442
Income from continuing operations attributable to Raytheon Company									$ 411	$ 389	$ 287
Diluted EPS from continuing operations attributable to Raytheon Company common stockholders									$ 1.47	$ 1.36	$ 0.98