Accumulated Other Comprehensive Loss (Components Of Accumulated Other Comprehensive Loss) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Accumulated Other Comprehensive Loss [Abstract]
Derivatives, Balance		$ (1,306)	$ (6,753)	$ 6,282
Unrealized Gains (Losses) on Investments, Balance		580	1,115	775
Postretirement Benefits, Balance	(17,653)	(132,695)	(82,047)	(64,796)
Proportionate Share Of Telesat Other Comprehensive Loss, Balance	(19,741)	(21,054)	(8,188)	(5,139)
Accumulated Other Comprehensive Loss, Balance	(37,394)	(154,475)	(95,873)	(62,878)
Derivatives, Period Change	1,306	5,447	(13,035)
Unrealized Gains (Losses) on Investments, Period Change	(580)	(535)	340
Postretirement Benefits, Period Change	115,042	(50,648)	(17,251)
Proportionate Share Of Telesat Other Comprehensive Loss, Period Change	1,313	(12,866)	(3,049)
Accumulated Other Comprehensive Loss, Period Change	$ 117,081	$ (58,602)	$ (32,995)