Consolidated Statements Of Cash Flows (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Net cash flows from operating activities:
Net income	$ 487,235,000	$ 10,786,000
Adjustments to reconcile net income to net cash used for operations:
Deferred income tax provision	263,133,000	18,072,000
Depreciation and amortization of property, equipment and leasehold improvements	26,247,000	16,735,000
Other amortization	23,894,000	7,052,000
Share-based compensation	3,892,000	1,024,000
Excess tax benefit from exercise of stock options		(15,000)
Provision for doubtful accounts	2,484,000	233,000
Net securities gains	(424,936,000)	(2,303,000)
(Income) losses related to associated companies	(401,908,000)	44,172,000
Distributions from associated companies	10,660,000	13,150,000
Net (gains) related to real estate, property and equipment, and other assets	(4,352,000)	(85,699,000)
Income related to Fortescue's Pilbara project, net of proceeds received	62,812,000	43,587,000
Gain on disposal of discontinued operations		(79,000)
Change in estimated litigation reserve		(2,241,000)
Net change in:
Trade, notes and other receivables	(28,591,000)	(13,363,000)
Inventory	(1,432,000)	(2,514,000)
Prepaids and other assets	4,574,000	522,000
Trade payables and expense accruals	(71,947,000)	(55,936,000)
Other liabilities	11,092,000	(4,382,000)
Income taxes payable	(5,128,000)	(8,201,000)
Other	(416,000)	1,625,000
Net cash used for operating activities	(42,687,000)	(17,775,000)
Net cash flows from investing activities:
Acquisition of property, equipment and leasehold improvements	(18,575,000)	(4,052,000)
Acquisitions of and capital expenditures for real estate investments	(1,248,000)	(4,452,000)
Proceeds from disposals of real estate, property and equipment, and other assets	1,979,000	15,811,000
Net change in restricted cash	4,676,000	(187,000)
Proceeds from (payments related to) disposal of discontinued operations, net of expenses and cash of operations sold	(384,000)	951,000
Advances on notes and other receivables	(451,000)	(2,366,000)
Collections on notes, loans and other receivables	6,068,000	4,957,000
Investments in associated companies	(498,000)	(890,000)
Capital distributions and loan repayment from associated companies	8,886,000	4,858,000
Purchases of investments (other than short-term)	(558,688,000)	(395,591,000)
Proceeds from maturities of investments	75,162,000	145,151,000
Proceeds from sales of investments	1,022,731,000	54,223,000
Other		2,066,000
Net cash provided by (used for) investing activities	539,658,000	(179,521,000)
Net cash flows from financing activities:
Issuance of debt, net of issuance costs	70,433,000	145,066,000
Reduction of debt	(525,940,000)	(73,156,000)
Issuance of common shares		1,340,000
Excess tax benefit from exercise of stock options		15,000
Other	(4,663,000)	(3,377,000)
Net cash provided by (used for) financing activities	(460,170,000)	69,888,000
Net increase (decrease) in cash and cash equivalents	36,801,000	(127,408,000)
Cash and cash equivalents at January 1,	168,490,000	441,340,000
Cash and cash equivalents at March 31,	205,291,000	313,932,000
Supplemental disclosures of cash flow information:
Interest	56,466,000	55,472,000
Income tax payments, net	$ 14,941,000	$ 12,214,000