Consolidated Statements Of Comprehensive Income (Loss) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Consolidated Statements Of Comprehensive Income (Loss) [Abstract]
Net income	$ 864,641	$ 24,956	$ 1,940,236
Other comprehensive income (loss):
Net unrealized holding gains (losses) on investments arising during the period, net of income tax provision (benefit) of $53,903, $(171,702) and $(21,983)	97,086	(309,256)	813,107
Less: reclassification adjustment for net (gains) losses included in net income (loss), net of income tax provision (benefit) of $(162,014), $(245,597), and $(3,146)	(291,807)	(442,350)	(97,514)
Net change in unrealized holding gains (losses) on investments, net of income tax provision (benefit) of $(108,111), $(417,299), and $(25,129)	(194,721)	(751,606)	715,593
Net unrealized foreign exchange gains (losses) arising during the period, net of income tax provision (benefit) of $(1,626), $372, and $(1)	(2,929)	670	(100)
Less: reclassification adjustment for foreign exchange gains (losses) included in net income (loss), net of income tax provision (benefit) of $0, $0, and $(96)			(7,762)
Net change in unrealized foreign exchange gains (losses), net of income tax provision (benefit) of $(1,626), $372, and $(97)	(2,929)	670	(7,862)
Net unrealized gains (losses) on derivatives arising during the period, net of income tax provision (benefit) of $(86), $0, and $4	(154)		306
Less: reclassification adjustment for derivative gains (losses) included in net income (loss), net of income tax provision (benefit) of $0, $0 and $0
Net change in unrealized derivative gains (losses), net of income tax provision (benefit) of $(86), $0, and $4	(154)		306
Net pension and postretirement gain (loss) arising during the period, net of income tax provision (benefit) of $(6,998), $(13,919), and $132	(12,606)	(25,070)	(23,189)
Less: reclassification adjustment for pension and postretirement (gains) losses included in net income (loss), net of income tax provision (benefit) of $1,731, $590, and $245	3,118	1,064	17,483
Net change in pension liability and postretirement benefits, net of income tax provision (benefit) of $(5,267), $(13,329), and $377	(9,488)	(24,006)	(5,706)
Other comprehensive income (loss), net of income taxes	(207,292)	(774,942)	702,331
Comprehensive income (loss)	657,349	(749,986)	2,642,567
Comprehensive (income) loss attributable to the noncontrolling interest	2,060	275	(924)
Comprehensive (income) attributable to the redeemable noncontrolling interests	(12,235)
Comprehensive income (loss) attributable to Leucadia National Corporation common shareholders	$ 647,174	$ (749,711)	$ 2,641,643