Shareholders' Equity - Adjustments to Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Class of Stock [Line Items]
Net interest income reclassified from other comprehensive income	$ (584)		$ (467)		$ (1,093)	$ (934)
Compensation and employee benefits expenses	1,046		1,077		2,278	2,319
Total reclassifications into (out of) Accumulated other comprehensive loss	(747)	$ (604)	(763)	$ (519)	(1,351)	(1,282)
Other comprehensive income (loss), cash flow hedge, gain (loss), reclassification, tax	3		7		9	13
Other comprehensive (income) loss, actuarial losses, tax	1		1		7	4
Reclassification out of Accumulated Other Comprehensive Income
Class of Stock [Line Items]
Total reclassifications into (out of) Accumulated other comprehensive loss	(4)		(16)		(5)	(23)
Reclassification out of Accumulated Other Comprehensive Income | Net Unrealized Gains (Losses) on Cash Flow Hedges
Class of Stock [Line Items]
Net interest income reclassified from other comprehensive income	(6)		(18)		(22)	(33)
Reclassification out of Accumulated Other Comprehensive Income | Amortization of Actuarial Losses
Class of Stock [Line Items]
Compensation and employee benefits expenses	$ 2		$ 2		$ 17	$ 10