Commitments and Contingencies (Details)			1 Months Ended		3 Months Ended	9 Months Ended		0 Months Ended
	Sep. 30, 2013 USD ($)	Dec. 31, 2012 USD ($)	May 31, 2010 Opry Mills Mall Limited Partnership [Member] USD ($)	Dec. 31, 2012 Mazeikiu Nafta [Member] USD ($)	Sep. 30, 2013 Commitments to fund certain limited partnerships or subsidiaries [Member] USD ($)	Sep. 30, 2013 Commitments to fund certain limited partnerships or subsidiaries [Member] USD ($)	Jun. 15, 2011 Commitments to fund certain limited partnerships or subsidiaries [Member] Subsidiaries [Member] Term Credit Agreement [Member] USD ($)	Mar. 20, 2012 Commitments to fund certain limited partnerships or subsidiaries [Member] Subsidiaries [Member] Five-Year Agreement [Member] USD ($)	Oct. 14, 2010 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	81,000,000	104,000,000			35,000,000	35,000,000	450,000,000	400,000,000	650,000,000
Term of credit agreement								5 years
Letters of credit outstanding	71,000,000	74,000,000
Commitments funded					$ 7,000,000	$ 13,000,000