Variable Interest Entities - Carrying Amounts and Classification of Significant Variable Interests (Details) - USD ($) $ in Thousands		Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2013	[1]
Variable Interest Entity [Line Items]
Cash and cash equivalents		$ 2,625,550	$ 1,796,062	$ 2,649,831	$ 1,538,779
Non-marketable and other securities	[2]	645,506	1,728,140
Accrued interest receivable and other assets	[2]	576,342	555,289
Total assets		40,236,118	39,339,950
Other liabilities		614,690	483,493
Total liabilities		37,046,646	$ 35,288,216
Maximum Exposure to Loss in Unconsolidated VIEs		340,972
Consolidated
Variable Interest Entity [Line Items]
Cash and cash equivalents		22,203
Non-marketable and other securities		200,695
Accrued interest receivable and other assets		659
Total assets		223,557
Other liabilities		282
Accrued expenses and other liabilities		0
Total liabilities		282
Maximum Exposure to Loss in Unconsolidated VIEs		223,300
Unconsolidated
Variable Interest Entity [Line Items]
Non-marketable and other securities		340,972
Total assets		340,972
Accrued expenses and other liabilities		63,637
Total liabilities		63,637
Maximum Exposure to Loss in Unconsolidated VIEs		$ 341,000

[1] Cash and cash equivalents at December 31, 2014 included $15.0 million recognized in assets held-for-sale in conjunction with the SVBIF Sale Transaction. On April 13, 2015 we received net proceeds of $39.3 million consisting of the sales price of $48.6 million less $9.3 million of cash and cash equivalents held by SVBIF that were sold.

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