Variable Interest Entities - Additional Information (Details) $ in Thousands		Sep. 30, 2015 USD ($) entity	Dec. 31, 2014 USD ($)		Sep. 30, 2014 USD ($)	[1]	Dec. 31, 2013 USD ($)
Variable Interest Entity [Line Items]
Number of deconsolidated entities | entity		16
Assets		$ (41,730,982)	$ (39,337,869)
Total equity		$ (3,314,228)	(4,051,734)	[1]	$ (3,936,168)		$ (3,074,693)
Number of consolidated entities | entity		5
Non-marketable and other securities	[2]	$ 650,555	$ 1,728,140
Consolidated
Variable Interest Entity [Line Items]
Assets		(223,699)
Non-marketable and other securities		204,555
Cumulative-Effect Adjustment, Deconsolidation of Variable Interest Entity
Variable Interest Entity [Line Items]
Assets		1,100,000
Total equity		1,200,000
Low Income Housing Tax Credit Funds | Consolidated
Variable Interest Entity [Line Items]
Non-marketable and other securities		125,500
Unfunded commitments | Consolidated
Variable Interest Entity [Line Items]
Non-marketable and other securities		$ 65,300

[1] Prior period amounts have been revised to reflect the retrospective application of new accounting guidance adopted in the first quarter of 2015 related to our investments in qualified affordable housing projects (ASU 2014-01). See Note 1— "Basis of Presentation" of the "Notes to Interim Consolidated Financial Statements" under Part I, Item 1 in this report.

[2] Prior period amounts have been revised to reflect the retrospective application of new accounting guidance adopted in the first quarter of 2015 related to our investments in qualified affordable housing projects (ASU 2014-01). See Note 1— "Basis of Presentation" of the "Notes to Interim Consolidated Financial Statements" under Part I, Item 1 in this report.