Securities Financing Activities (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Offsetting Liabilities [Line Items]
Short-term Debt	$ 26,329	$ 24,828
Securities Sold under Agreements to Repurchase
Offsetting Liabilities [Line Items]
Short-term Debt	1,589	2,427
Securities Sold under Agreements to Repurchase | U.S. Treasury
Offsetting Liabilities [Line Items]
Short-term Debt	10	12
Securities Sold under Agreements to Repurchase | State and Municipal
Offsetting Liabilities [Line Items]
Short-term Debt	428	415
Securities Sold under Agreements to Repurchase | Agency MBS – residential
Offsetting Liabilities [Line Items]
Short-term Debt	500	1,500
Securities Sold under Agreements to Repurchase | Corporate and other debt securities
Offsetting Liabilities [Line Items]
Short-term Debt	651	500
Securities Sold under Agreements to Repurchase | Overnight and Continuous
Offsetting Liabilities [Line Items]
Short-term Debt	959	847
Securities Sold under Agreements to Repurchase | Overnight and Continuous | U.S. Treasury
Offsetting Liabilities [Line Items]
Short-term Debt	10	12
Securities Sold under Agreements to Repurchase | Overnight and Continuous | State and Municipal
Offsetting Liabilities [Line Items]
Short-term Debt	428	415
Securities Sold under Agreements to Repurchase | Overnight and Continuous | Agency MBS – residential
Offsetting Liabilities [Line Items]
Short-term Debt	0	0
Securities Sold under Agreements to Repurchase | Overnight and Continuous | Corporate and other debt securities
Offsetting Liabilities [Line Items]
Short-term Debt	521	420
Securities Sold under Agreements to Repurchase | Up to 30 days
Offsetting Liabilities [Line Items]
Short-term Debt	580	1,580
Securities Sold under Agreements to Repurchase | Up to 30 days | U.S. Treasury
Offsetting Liabilities [Line Items]
Short-term Debt	0	0
Securities Sold under Agreements to Repurchase | Up to 30 days | State and Municipal
Offsetting Liabilities [Line Items]
Short-term Debt	0	0
Securities Sold under Agreements to Repurchase | Up to 30 days | Agency MBS – residential
Offsetting Liabilities [Line Items]
Short-term Debt	500	1,500
Securities Sold under Agreements to Repurchase | Up to 30 days | Corporate and other debt securities
Offsetting Liabilities [Line Items]
Short-term Debt	80	$ 80
Securities Sold under Agreements to Repurchase | 30-90 days
Offsetting Liabilities [Line Items]
Short-term Debt	50
Securities Sold under Agreements to Repurchase | 30-90 days | U.S. Treasury
Offsetting Liabilities [Line Items]
Short-term Debt	0
Securities Sold under Agreements to Repurchase | 30-90 days | State and Municipal
Offsetting Liabilities [Line Items]
Short-term Debt	0
Securities Sold under Agreements to Repurchase | 30-90 days | Agency MBS – residential
Offsetting Liabilities [Line Items]
Short-term Debt	0
Securities Sold under Agreements to Repurchase | 30-90 days | Corporate and other debt securities
Offsetting Liabilities [Line Items]
Short-term Debt	$ 50