Earnings (Loss) Per Common Share (Earnings Per Share Computation) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income attributable to Leucadia National Corporation common shareholders	$ 55,595	$ (173,173)	$ 16,406	$ 380,759	$ (9,763)	$ 54,679	$ 65,074	$ 94,316	$ 279,587	$ 204,306	$ 369,240
Less: Allocation of earnings to participating securities									(4,711)	(4,761)	(4,919)
Net income attributable to Leucadia National Corporation common shareholders for basic earnings (loss) per share									274,876	199,545	364,321
Less: Adjustment to allocation of earnings to participating securities related to diluted shares (1)									(34)	(75)	(110)
Mandatorily redeemable convertible preferred share dividends									0	0	3,397
Interest on 3.75% Convertible Notes									0	739	2,635
Net income attributable to Leucadia National Corporation common shareholders for diluted earnings (loss) per share									$ 274,842	$ 200,209	$ 370,243
Denominator for basic earnings (loss) per share – weighted average shares (shares)	369,840,000	372,547,000	373,654,000	373,541,000	373,617,000	373,347,000	371,979,000	368,487,000	372,430,000	371,889,000	339,673,000
Stock options (shares)									1,000	29,000	55,000
Warrants (shares)									0	0	0
Mandatorily redeemable convertible preferred shares (shares)									0	0	3,468,000
Denominator for diluted earnings (loss) per share (shares)	369,840,000	372,547,000	373,662,000	377,713,000	373,617,000	373,375,000	373,179,000	377,348,000	372,431,000	373,333,000	347,734,000
Weighted average shares of participating securities									6,500,000	9,040,900	9,353,400
Dividends declared on participating securities									$ 1,500	$ 2,200	$ 2,800
3.875% Convertible Senior Debentures, due November 1, 2029 [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Convertible Debenture/Notes (shares)									0	0	0
3.75% Convertible Senior Subordinated Notes Due April 15, 2014 [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Convertible Debenture/Notes (shares)									0	1,415,000	4,538,000