Variable Interest Entities - Carrying Amounts and Classification of Significant Variable Interests (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Variable Interest Entity [Line Items]
Cash and cash equivalents	$ 15,687,776	$ 6,781,783
Non-marketable and other equity securities	1,547,363	1,213,829
Accrued interest receivable and other assets	2,316,979	1,745,233
Total assets	96,916,771	71,004,903
Other liabilities	3,067,221	2,041,752
Total liabilities	88,949,391	64,383,823
Maximum exposure to loss in unconsolidated VIEs	771,329	689,360
Investments in qualified affordable housing projects, net	560,983	458,476
Consolidated
Variable Interest Entity [Line Items]
Cash and cash equivalents	14,082	7,629
Non-marketable and other equity securities	318,356	270,057
Accrued interest receivable and other assets	853	1,117
Total assets	333,291	278,803
Other liabilities	1,500	2,854
Total liabilities	1,500	2,854
Maximum exposure to loss in unconsolidated VIEs	331,800
Unconsolidated
Variable Interest Entity [Line Items]
Cash and cash equivalents	0	0
Non-marketable and other equity securities	771,329	689,360
Accrued interest receivable and other assets	0	0
Total assets	771,329	689,360
Other liabilities	332,031	302,031
Total liabilities	332,031	302,031
Maximum exposure to loss in unconsolidated VIEs	771,300
Unconsolidated | Non-marketable securities
Variable Interest Entity [Line Items]
Maximum exposure to loss in unconsolidated VIEs	$ 771,329	$ 689,360