Shareholders' Equity - Adjustments to Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Class of Stock [Line Items]
Net interest income reclassified from other comprehensive income	$ (660)			$ (487)			$ (1,753)	$ (1,421)
Compensation and employee benefits expenses	1,042			1,054			3,320	3,373
Total reclassifications into (out of) Accumulated other comprehensive loss	(690)	$ (747)	$ (604)	(714)	$ (763)	$ (519)	(2,041)	(1,996)
Other comprehensive income (loss), cash flow hedge, gain (loss), reclassification, tax	(6)			6			3	19
Other comprehensive (income) loss, actuarial losses, tax	1			1			8	5
Amounts Reclassified (into) out of Earnings
Class of Stock [Line Items]
Total reclassifications into (out of) Accumulated other comprehensive loss	18			(16)			13	(39)
Amounts Reclassified (into) out of Earnings | Net Unrealized Gains (Losses) on Cash Flow Hedges
Class of Stock [Line Items]
Net interest income reclassified from other comprehensive income	16			(18)			(6)	(51)
Amounts Reclassified (into) out of Earnings | Amortization of Actuarial Losses
Class of Stock [Line Items]
Compensation and employee benefits expenses	$ 2			$ 2			$ 19	$ 12