Earnings (Loss) Per Common Share (Earnings Per Share Computation) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Earnings Per Share [Line Items]
Net income attributable to Leucadia National Corporation common shareholders for basic earnings (loss) per share	$ 490,877	$ 10,507
Interest on 3 3/4% Convertible Notes	656
Net income attributable to Leucadia National Corporation common shareholders for diluted earnings (loss) per share	$ 491,533	$ 10,507
Denominator for basic earnings (loss) per share - weighted average shares	244,583	244,082
Stock options	35	158
Warrants		380
3 3/4 % Convertible Notes	4,327
Denominator for diluted earnings (loss) per share	248,945	244,620
Convertible Notes [Member]
Earnings Per Share [Line Items]
Convertible notes interest rate	3.75%	3.75%