Net Interest Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Interest income:
Interest-bearing deposits with banks	$ 693	$ 202	$ 2,031	$ 281
Investment securities:
Investment securities available-for-sale	464	176	1,218	452
Investment securities held-to-maturity	314	271	954	672
Total investment securities	778	447	2,172	1,124
Securities purchased under resale agreements	65	57	223	105
Loans	492	256	1,330	627
Other interest-earning assets	300	139	831	189
Total interest income	2,328	1,101	6,587	2,326
Interest expense:
Interest-bearing deposits	1,332	300	3,479	260
Securities sold under repurchase agreements	6	2	28	5
Short-term borrowings	2	0	34	1
Long-term debt	241	97	635	234
Other interest-bearing liabilities	123	42	330	73
Interest expense	1,704	441	4,506	573
Net interest income	$ 624	$ 660	$ 2,081	$ 1,753