Variable Interest Entities - Carrying Amounts and Classification of Significant Variable Interests (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Variable Interest Entity [Line Items]
Cash and cash equivalents	$ 3,854,244	$ 2,545,750	$ 1,854,457	$ 1,503,257
Non-marketable and other securities	630,670	622,552
Amortization Method Qualified Affordable Housing Project Investments	140,381	112,447
Accrued interest receivable and other assets	1,044,125	672,688
Total assets	48,400,379	44,683,660
Total liabilities	44,360,344	40,906,623
Maximum exposure to loss in unconsolidated VIEs	323,426	314,810
Qualified Affordable Housing Project Investments, Commitment	86,545	58,095
Consolidated
Variable Interest Entity [Line Items]
Cash and cash equivalents	7,440	11,469
Non-marketable and other securities	194,543	196,140
Accrued interest receivable and other assets	142	294
Total assets	202,125	207,903
Total liabilities	604	517
Maximum exposure to loss in unconsolidated VIEs	201,500
Accrued Liabilities and Other Liabilities	604	517
Unconsolidated
Variable Interest Entity [Line Items]
Cash and cash equivalents	0	0
Non-marketable and other securities	323,426	314,810
Accrued interest receivable and other assets	0	0
Total assets	323,426	314,810
Total liabilities	$ 86,545	$ 58,095