SECURITIES - Amortized Cost and Fair Value of Securities, by Contractual Maturities (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Schedule Of Securities [Line Items]
Available for sale, due in one year or less, amortized cost	$ 14
Available for sale, due after one year but within five years, amortized cost	577
Available for sale, due after five years but within ten years, amortized cost	96
Available for sale, due after ten years, amortized cost	46
Available for sale, with contractual maturities, amortized cost	733
Amortized Cost	3,760	$ 3,416
Available for sale, due in one year or less, fair value	14
Available for sale, due after one year but within five years, fair value	530
Available for sale, due after five years but within ten years, fair value	94
Available for sale, due after ten years, fair value	45
Available for sale, with contractual maturities, fair value	683
Fair Value	3,392	3,426
Held to maturity, due in one year or less, amortized cost	1
Held to maturity, due after one year but within five years, amortized cost	31
Held to maturity, due after five years but within ten years, amortized cost	152
Held to maturity, due after ten years, amortized cost	793
Held to maturity, with contractual maturities, amortized cost	977
Amortized Cost	3,820	3,463
Held to maturity, due in one year or less, fair value	1
Held to maturity, due after one year but within five years, fair value	29
Held to maturity, due after five years but within ten years, fair value	136
Held to maturity, due after ten years, fair value	650
Held to maturity, with contractual maturities, fair value	816
Fair Value	3,349	3,506
Agency mortgage-backed securities
Schedule Of Securities [Line Items]
Available-for-sale, amortized cost	1,427
Amortized Cost	1,427	1,342
Available for sale, fair value	1,280
Fair Value	1,280	1,357
Held to maturity, amortized cost	1,183
Amortized Cost	1,183	1,191
Held to maturity, fair value	1,040
Fair Value	1,040	1,201
Agency collateralized mortgage obligations
Schedule Of Securities [Line Items]
Available-for-sale, amortized cost	1,158
Amortized Cost	1,158	1,192
Available for sale, fair value	1,022
Fair Value	1,022	1,186
Held to maturity, amortized cost	992
Amortized Cost	992	930
Held to maturity, fair value	875
Fair Value	875	923
Commercial mortgage-backed securities
Schedule Of Securities [Line Items]
Available-for-sale, amortized cost	442
Amortized Cost	442	294
Available for sale, fair value	407
Fair Value	407	297
Held to maturity, amortized cost	668
Amortized Cost	668	323
Held to maturity, fair value	618
Fair Value	$ 618	$ 324

Schedule Of Securities [Line Items]

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