Net Interest Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Interest income:
Interest-bearing deposits with banks	$ 878	$ 693	$ 2,805	$ 2,031
Investment securities:
Investment securities available-for-sale	733	464	1,978	1,218
Investment securities held-to-maturity	266	314	837	954
Total investment securities	999	778	2,815	2,172
Securities purchased under resale agreements	183	65	516	223
Loans	579	492	1,687	1,330
Other interest-earning assets	442	300	1,145	831
Total interest income	3,081	2,328	8,968	6,587
Interest expense:
Interest-bearing deposits	1,696	1,332	4,973	3,479
Securities sold under repurchase agreements	28	6	110	28
Other short-term borrowings	176	2	444	34
Long-term debt	267	241	792	635
Other interest-bearing liabilities	191	123	475	330
Total interest expense	2,358	1,704	6,794	4,506
Net interest income	$ 723	$ 624	$ 2,174	$ 2,081