Investment Securities - Schedule of Amortized Cost and Fair Value by Contractual Maturity (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Amortized Cost
Within 1 year	$ 0
After 1 year through 5 years	0
After 5 years through 10 years	0
After 10 years	0
Subtotal	0
Government agency issued MBS and CMO	1,216
Total	1,216
Fair Value
Within 1 year	0
After 1 year through 5 years	0
After 5 years through 10 years	0
After 10 years	0
Subtotal	0
Government agency issued MBS and CMO	1,073
Fair Value	1,073	$ 1,083
Amortized Cost
Within 1 year	12
After 1 year through 5 years	124
After 5 years through 10 years	527
After 10 years	1,122
Subtotal	1,785
Government agency issued MBS and CMO	7,056
Securities available for sale, amortized cost	8,841	8,930
Fair Value
Within 1 year	11
After 1 year through 5 years	116
After 5 years through 10 years	508
After 10 years	1,020
Subtotal	1,655
Government agency issued MBS and CMO	6,510
Securities available-for-sale	$ 8,165	$ 7,896