Financial Information of L-3 Communications and Its Subsidiaries (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended							12 Months Ended										12 Months Ended							12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011 L-3 Holdings' Common Stock	Dec. 31, 2010 L-3 Holdings' Common Stock	Dec. 31, 2009 L-3 Holdings' Common Stock	Dec. 31, 2008 L-3 Holdings' Common Stock	Dec. 31, 2011 Retained Earnings	Dec. 31, 2010 Retained Earnings	Dec. 31, 2009 Retained Earnings	Dec. 31, 2011 L-3 Communications [Member]	Dec. 31, 2010 L-3 Communications [Member]	Dec. 31, 2009 L-3 Communications [Member]	Dec. 31, 2011 L-3 Communications [Member] L-3 Holdings' Common Stock	Dec. 31, 2010 L-3 Communications [Member] L-3 Holdings' Common Stock	Dec. 31, 2009 L-3 Communications [Member] L-3 Holdings' Common Stock	Dec. 31, 2008 L-3 Communications [Member] L-3 Holdings' Common Stock	Dec. 31, 2011 L-3 Communications [Member] Additional Paid-in Capital	Dec. 31, 2010 L-3 Communications [Member] Additional Paid-in Capital	Dec. 31, 2009 L-3 Communications [Member] Additional Paid-in Capital	Dec. 31, 2011 L-3 Communications [Member] Treasury Stock	Dec. 31, 2010 L-3 Communications [Member] Treasury Stock	Dec. 31, 2009 L-3 Communications [Member] Treasury Stock	Dec. 31, 2008 L-3 Communications [Member] Treasury Stock	Dec. 31, 2011 L-3 Communications [Member] Retained Earnings	Dec. 31, 2010 L-3 Communications [Member] Retained Earnings	Dec. 31, 2009 L-3 Communications [Member] Retained Earnings	Dec. 31, 2011 L-3 Communications [Member] Accumulated Other Comprehensive (Loss) Income	Dec. 31, 2010 L-3 Communications [Member] Accumulated Other Comprehensive (Loss) Income	Dec. 31, 2009 L-3 Communications [Member] Accumulated Other Comprehensive (Loss) Income
Condensed Combining Statements of Equity
Beginning Balance																			$ 6,764	$ 6,567	$ 5,858	$ 0	$ 0	$ 0	$ 0	$ 4,801	$ 4,449	$ 4,136	$ 0	$ 0	$ 0	$ 0	$ 2,219	$ 2,284	$ 2,054	$ (256)	$ (166)	$ (332)
Beginning Balance, Shares												99.0	108.6	115.4	118.6							100.0	100.0	100.0	100.0
Net income attributable to L-3	277	238	246	207	272	241	231	222	968	966	911					956	955	901	956	955	901												956	955	901
Contributions from L-3 Holdings																			263	352	313					263	352	313
Dividends to L-3 Holdings																			(1,157)	(1,018)	(670)												(1,157)	(1,018)	(670)
Comprehensive income (loss)									(198)	(90)	166								(198)	(90)	166															(198)	(90)	166
Other																			7	(2)	(1)												7	(2)	(1)
Ending Balance																			$ 6,635	$ 6,764	$ 6,567	$ 0	$ 0	$ 0	$ 0	$ 5,064	$ 4,801	$ 4,449	$ 0	$ 0	$ 0	$ 0	$ 2,025	$ 2,219	$ 2,284	$ (454)	$ (256)	$ (166)
Ending Balance, Shares												99.0	108.6	115.4	118.6							100.0	100.0	100.0	100.0