Investment Securities - Schedule of Investments within the Available for Sale Portfolio that had Unrealized Losses (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Fair Value
Less than 12 months	$ 1,304	$ 825
12 months or longer	5,305	5,529
Total fair value	6,609	6,354
Unrealized Losses
Less than 12 months	(5)	(2)
12 months or longer	(702)	(693)
Total unrealized losses	(707)	(695)
Government agency issued MBS
Fair Value
Less than 12 months	359	190
12 months or longer	2,700	2,791
Total fair value	3,059	2,981
Unrealized Losses
Less than 12 months	(2)	(1)
12 months or longer	(329)	(331)
Total unrealized losses	(331)	(332)
Government agency issued CMO
Fair Value
Less than 12 months	556	353
12 months or longer	1,623	1,706
Total fair value	2,179	2,059
Unrealized Losses
Less than 12 months	(1)	0
12 months or longer	(237)	(229)
Total unrealized losses	(238)	(229)
Other U.S. government agencies
Fair Value
Less than 12 months	328	281
12 months or longer	771	796
Total fair value	1,099	1,077
Unrealized Losses
Less than 12 months	(1)	(1)
12 months or longer	(105)	(108)
Total unrealized losses	(106)	(109)
States and municipalities
Fair Value
Less than 12 months	61	1
12 months or longer	211	236
Total fair value	272	237
Unrealized Losses
Less than 12 months	(1)	0
12 months or longer	(31)	(25)
Total unrealized losses	$ (32)	$ (25)