Consolidated Statements Of Comprehensive Income (Loss) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Consolidated Statements Of Comprehensive Income (Loss) [Abstract]
Net income	$ 487,235	$ 10,786
Other comprehensive income (loss):
Net unrealized holding gains (losses) on investments arising during the period, net of income tax provision (benefit) of $(9,201) and $(37,592)	(16,571)	(67,707)
Less: reclassification adjustment for net (gains) losses included in net income, net of income tax provision (benefit) of $123,791 and $(773)	(222,964)	1,391
Net change in unrealized holding gains (losses) on investments, net of income tax provision (benefit) of $(132,992) and $(36,819)	(239,535)	(66,316)
Net unrealized foreign exchange gains (losses) arising during the period, net of income tax provision (benefit) of $(1,070) and $698	(1,927)	1,258
Less: reclassification adjustment for foreign exchange gains (losses) included in net income, net of income tax provision (benefit) of $0 and $0
Net change in unrealized foreign exchange gains (losses), net of income tax provision (benefit) of $(1,070) and $698	(1,927)	1,258
Net unrealized gains (losses) on derivatives arising during the period, net of income tax provision (benefit) of $(89) and $0	(160)
Less: reclassification adjustment for derivative gains (losses) included in net income, net of income tax provision (benefit) of $0 and $0
Net change in unrealized derivative gains (losses), net of income tax provision (benefit) of $(89) and $0	(160)
Net pension and postretirement gain (loss) arising during the period, net of income tax provision (benefit) of $0 and $0
Less: amortization of actuarial net loss included in net periodic pension cost, net of income tax provision (benefit) of $433 and $(1)	780
Net change in pension liability and postretirement benefits, net of income tax provision (benefit) of $433 and $(1)	780
Other comprehensive (loss), net of income taxes	(240,842)	(65,058)
Comprehensive income (loss)	246,393	(54,272)
Comprehensive (income) attributable to the noncontrolling interest	(202)	(279)
Comprehensive loss attributable to the redeemable noncontrolling interest	3,844
Comprehensive income (loss) attributable to Leucadia National Corporation common shareholders	$ 250,035	$ (54,551)