Commitments and Contingencies (Details)			1 Months Ended		3 Months Ended	6 Months Ended		0 Months Ended
	Jun. 30, 2013 USD ($)	Dec. 31, 2012 USD ($)	May 31, 2010 Opry Mills Mall Limited Partnership [Member] USD ($)	Dec. 31, 2012 Mazeikiu Nafta [Member] USD ($)	Jun. 30, 2013 Commitments to fund certain limited partnerships or subsidiaries [Member] USD ($)	Jun. 30, 2013 Commitments to fund certain limited partnerships or subsidiaries [Member] USD ($)	Apr. 02, 2012 Commitments to fund certain limited partnerships or subsidiaries [Member] Subsidiaries [Member] Term Credit Agreement [Member] USD ($)	Mar. 20, 2012 Commitments to fund certain limited partnerships or subsidiaries [Member] Subsidiaries [Member] Five-Year Agreement [Member]	Apr. 02, 2012 Commitments to fund certain limited partnerships or subsidiaries [Member] Subsidiaries [Member] Five-Year Agreement [Member] USD ($)	Apr. 02, 2012 Commitments to fund certain limited partnerships or subsidiaries [Member] Subsidiaries [Member] Euro Facility Agreement [Member] EUR (€)
Legal, Guarantees and Indemnifications
Damages sought			$ 200,000,000	$ 125,000,000
Amount of coverage for damages contended by the insurers			50,000,000
Difference amount of damages sought by the client			150,000,000
Maximum potential funding under commitments	95,000,000	104,000,000			42,000,000	42,000,000	450,000,000		400,000,000	650,000,000
Term of credit agreement								5 years
Letters of credit outstanding	69,000,000	74,000,000
Commitments funded					$ 3,000,000	$ 6,000,000