Borrowed Funds (Narrative) (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Borrowed funds	$ 54,633	$ 30,784
Parent Company
Debt Instrument [Line Items]
Borrowed funds	10,022	11,351
Parent Company | Senior debt
Debt Instrument [Line Items]
Borrowed funds	8,296	10,369
Basis adjustments - Fair value accounting hedges	(810)
Parent Company | Subordinated debt
Debt Instrument [Line Items]
Borrowed funds	1,520	777
Basis adjustments - Fair value accounting hedges	(75)
Subsidiaries
Debt Instrument [Line Items]
Borrowed funds	40,696	16,306
Subsidiaries | Senior debt
Debt Instrument [Line Items]
Borrowed funds	5,061	10,292
Basis adjustments - Fair value accounting hedges	(272)
Subsidiaries | Subordinated debt
Debt Instrument [Line Items]
Borrowed funds	5,560	$ 6,014
Basis adjustments - Fair value accounting hedges	$ (254)