Shareholders' Equity - Adjustments to Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Class of Stock [Line Items]
Gains (losses) from sales of available-for-sale securities, net	$ (79)	$ (294)	$ (2)
Net interest income	2,923	2,759	2,544
Compensation and employee benefits expenses	4,697	4,744	4,428
Net income	2,687	1,944	2,774
Net realized gains from sales of available-for-sale securities, tax	21	81	1
Amortization of net unrealized gain (loss), before adjustment, tax	137	81	96
Net realized gains from sales of available-for-sale securities, tax	(14)	55	(13)
Other comprehensive (income) loss, actuarial losses, tax	0	0	(1)
Amounts Reclassified into Earnings
Class of Stock [Line Items]
Net income	414	582	122
Amounts Reclassified into Earnings | Net Unrealized Gains (Losses) on Investment Securities
Class of Stock [Line Items]
Gains (losses) from sales of available-for-sale securities, net	59	213	1
Amounts Reclassified into Earnings | AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Transferred to Held-To-Maturity, Parent
Class of Stock [Line Items]
Net interest income	393	215	169
Amounts Reclassified into Earnings | Net Unrealized Gains (Losses) on Cash Flow Hedges
Class of Stock [Line Items]
Net interest income	(40)	153	(36)
Amounts Reclassified into Earnings | Amortization of Actuarial Losses
Class of Stock [Line Items]
Compensation and employee benefits expenses	$ 2	$ 1	$ (12)