Consolidated Statements Of Comprehensive Income (Loss) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Consolidated Statements Of Comprehensive Income (Loss) [Abstract]
Net income (loss)	$ (187,768)	$ 186,458	$ 299,467	$ 197,244
Other comprehensive income (loss):
Net unrealized holding gains (losses) on investments arising during the period, net of income tax provision (benefit) of $(71,081), $22,319, $(80,282) and $(15,273)	(128,028)	40,199	(144,599)	(27,508)
Less: reclassification adjustment for net (gains) losses included in net income (loss), net of income tax provision (benefit) of $21, $193,537, $123,812 and $192,764	(36)	(348,584)	(223,000)	(347,193)
Net change in unrealized holding gains (losses) on investments, net of income tax provision (benefit) of $(71,102), $(171,218), $(204,094) and $(208,037)	(128,064)	(308,385)	(367,599)	(374,701)
Net unrealized foreign exchange gains (losses) arising during the period, net of income tax provision (benefit) of $(1,431), $460, $(2,501) and $1,158	(2,579)	828	(4,506)	2,086
Less: reclassification adjustment for foreign exchange gains (losses) included in net income (loss), net of income tax provision (benefit) of $0, $0, $0 and $0
Net change in unrealized foreign exchange gains (losses), net of income tax provision (benefit) of $(1,431), $460, $(2,501) and $1,158	(2,579)	828	(4,506)	2,086
Net unrealized gains (losses) on derivatives arising during the period, net of income tax provision (benefit) of $4, $0, $(85) and $0	7		(153)
Less: reclassification adjustment for derivative gains (losses) included in net income (loss), net of income tax provision (benefit) of $0, $0, $0 and $0
Net change in unrealized derivative gains (losses), net of income tax provision (benefit) of $4, $0, $(85) and $0	7		(153)
Net pension and postretirement gain (loss) arising during the period, net of income tax provision (benefit) of $0, $0, $0 and $0
Less: amortization of actuarial net loss included in net periodic pension cost, net of income tax provision (benefit) of $433, $(2), $866 and $(3)	778	(5)	1,558	(5)
Net change in pension liability and postretirement benefits, net of income tax provision (benefit) of $433, $(2), $866 and $(3)	778	(5)	1,558	(5)
Other comprehensive (loss), net of income taxes	(129,858)	(307,562)	(370,700)	(372,620)
Comprehensive (loss)	(317,626)	(121,104)	(71,233)	(175,376)
Comprehensive (income) loss attributable to the noncontrolling interest	297	(149)	95	(428)
Comprehensive (income) attributable to the redeemable noncontrolling interests	(9,780)		(5,936)
Comprehensive (loss) attributable to Leucadia National Corporation common shareholders	$ (327,109)	$ (121,253)	$ (77,074)	$ (175,804)