Interim Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash flows from operating activities:
Net income before noncontrolling interests	$ 60,545	$ 39,933
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	5,813	14,529
Provision for (reduction of) unfunded credit commitments	2,014	(258)
Changes in fair values of derivatives, net	757	(3,370)
Gains on investment securities, net	(27,438)	(7,839)
Depreciation and amortization	8,479	6,454
Amortization of premiums and discounts on available-for-sale securities, net	8,348	9,869
Tax (expense) benefit from stock exercises	(1,247)	790
Amortization of share-based compensation	5,826	5,149
Amortization of deferred loan fees	(15,040)	(15,488)
Deferred income tax expense	(19)	(1,570)
Losses from the write-off of premises and equipment	363	0
Changes in other assets and liabilities:
Accrued interest receivable and payable, net	(4,735)	(6,399)
Accounts receivable and payable, net	6,220	14,631
Income tax payable and receivable, net	6,236	14,013
Accrued compensation	(62,375)	(66,240)
Foreign exchange spot contracts, net	26,534	(21,154)
Other, net	(21,325)	6,078
Net cash used for operating activities	(1,044)	(10,872)
Cash flows from investing activities:
Purchases of available-for-sale securities	(219,987)	(1,777,958)
Proceeds from sales of available-for-sale securities	581	3,219
Proceeds from maturities and pay downs of available-for-sale securities	653,764	777,717
Purchases of nonmarketable securities (cost and equity method accounting)	(5,112)	(9,005)
Proceeds from sales of nonmarketable securities (cost and equity method accounting)	7,942	11,317
Purchases of nonmarketable securities (fair value accounting)	(30,342)	(29,440)
Proceeds from sales and distributions of nonmarketable securities (fair value accounting)	21,748	25,545
Net decrease (increase) in loans	108,971	(144,957)
Proceeds from recoveries of charged-off loans	1,367	3,436
Purchases of premises and equipment	(6,606)	(8,054)
Net cash provided by (used for) investing activities	532,326	(1,148,180)
Cash flows from financing activities:
Net increase in deposits	133,456	7,346
(Decrease) increase in short-term borrowings	(158,650)	849,380
Capital contributions from noncontrolling interests, net of distributions	(14,493)	17,073
Tax benefit from stock exercises	610	3,029
Proceeds from issuance of common stock and ESPP	18,061	17,900
Net cash (used for) provided by financing activities	(21,016)	894,728
Net increase (decrease) in cash and cash equivalents	510,266	(264,324)
Cash and cash equivalents at beginning of period	1,008,983	1,114,948
Cash and cash equivalents at end of period	1,519,249	850,624
Cash paid during the period for:
Interest	12,372	12,012
Income taxes	19,318	6,556
Noncash items during the period:
Unrealized (losses) gains on available-for-sale securities, net of tax	$ (12,409)	$ 2,451