Investment Securities - Components of Non-marketable and Other Equity Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Investment Holdings [Line Items]
Investments in qualified affordable housing projects, net	$ 616,997	$ 616,188
Non-marketable and other equity securities	1,857,761	1,802,235
Fair value accounting | Consolidated venture capital and private equity fund investments
Investment Holdings [Line Items]
Nonmarketable securities	96,016	88,937
Fair value accounting | Unconsolidated venture capital and private equity fund investments
Investment Holdings [Line Items]
Nonmarketable securities	178,407	184,886
Fair value accounting | Equity securities
Investment Holdings [Line Items]
Other equity securities in public companies (fair value accounting)	160,810	280,804
Fair value accounting | Other investments
Investment Holdings [Line Items]
Nonmarketable securities	200,367	60,975
Equity method accounting | Consolidated venture capital and private equity fund investments
Investment Holdings [Line Items]
Nonmarketable securities	394,349	362,192
Equity method accounting | Unconsolidated venture capital and private equity fund investments
Investment Holdings [Line Items]
Nonmarketable securities	394,349	362,192
Equity method accounting | Debt funds
Investment Holdings [Line Items]
Nonmarketable securities	5,813	5,444
Equity method accounting | Other investments
Investment Holdings [Line Items]
Nonmarketable securities	$ 205,002	$ 202,809