Variable Interest Entities - Carrying Amounts and Classification of Significant Variable Interests (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Variable Interest Entity [Line Items]
Cash and cash equivalents	$ 3,571,539	$ 2,923,075	$ 2,545,750	$ 1,503,257
Non-marketable and other equity securities	941,104	651,053
Accrued interest receivable and other assets	951,261	876,246
Total assets	56,927,979	51,214,467
Other liabilities	1,006,359	911,755
Total liabilities	51,663,136	46,895,052
Investments in Affordable Housing Projects [Abstract]
Investments in qualified affordable housing projects	318,575	174,214
Related other liabilities of unfunded credit commitments	205,685	100,891
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Cash and cash equivalents	9,058	6,674
Non-marketable and other equity securities	221,646	190,562
Accrued interest receivable and other assets	228	365
Total assets	230,932	197,601
Other liabilities	919	990
Total liabilities	919	990
Maximum Exposure to Loss in Unconsolidated VIEs	230,000
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Cash and cash equivalents	0	0
Non-marketable and other equity securities	568,272	346,097
Accrued interest receivable and other assets	0	0
Total assets	568,272	346,097
Other liabilities	205,685	100,891
Total liabilities	205,685	100,891
Maximum Exposure to Loss in Unconsolidated VIEs	$ 568,272	$ 346,097