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SECURITIES - Amortized Cost and Fair Value of Securities, by Contractual Maturities (Detail) - USD ($) $ in Millions | Jun. 30, 2019 | Dec. 31, 2018
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Schedule Of Securities [Line Items] |  |
Available for sale, due in one year or less, amortized cost | $ 123 |
Available for sale, due after one year but within five years, amortized cost | 194 |
Available for sale, due after five years but within ten years, amortized cost | 73 |
Available for sale, due after ten years, amortized cost | 100 |
Available for sale, with contractual maturities, amortized cost | 490 |
Amortized Cost | 3,268 | $ 3,401
Available for sale, due in one year or less, fair value | 123 |
Available for sale, due after one year but within five years, fair value | 195 |
Available for sale, due after five years but within ten years, fair value | 72 |
Available for sale, due after ten years, fair value | 100 |
Available for sale, with contractual maturities, fair value | 490 |
Total securities available for sale, fair value | 3,279 | 3,341
Held to maturity, due in one year or less, amortized cost | 33 |
Held to maturity, due after one year but within five years, amortized cost | 181 |
Held to maturity, due after five years but within ten years, amortized cost | 97 |
Held to maturity, due after ten years, amortized cost | 988 |
Held to maturity, with contractual maturities, amortized cost | 1,299 |
Amortized Cost | 3,079 | 3,254
Held to maturity, due in one year or less, fair value | 33 |
Held to maturity, due after one year but within five years, fair value | 179 |
Held to maturity, due after five years but within ten years, fair value | 99 |
Held to maturity, due after ten years, fair value | 1,000 |
Securities held to maturity, with contractual maturities, fair value | 1,311 |
Held-to-maturity, fair value, net | 3,093 | 3,155
Agency Mortgage-Backed Securities [Member] |  |
Schedule Of Securities [Line Items] |  |
Available-for-sale, amortized cost | 1,318 |
Amortized Cost | 1,318 | 1,465
Available for sale, fair value | 1,315 |
Total securities available for sale, fair value | 1,315 | 1,429
Held-to-maturity, amortized cost | 952 |
Amortized Cost | 952 | 1,036
Held-to-maturity, fair value | 952 |
Held-to-maturity, fair value, net | 952 | 1,010
Agency Collateralized Mortgage Obligations [Member] |  |
Schedule Of Securities [Line Items] |  |
Available-for-sale, amortized cost | 1,233 |
Amortized Cost | 1,233 | 1,179
Available for sale, fair value | 1,242 |
Total securities available for sale, fair value | 1,242 | 1,161
Held-to-maturity, amortized cost | 728 |
Amortized Cost | 728 | 794
Held-to-maturity, fair value | 726 |
Held-to-maturity, fair value, net | 726 | 771
Commercial Mortgage-Backed Securities [Member] |  |
Schedule Of Securities [Line Items] |  |
Available-for-sale, amortized cost | 227 |
Amortized Cost | 227 | 229
Available for sale, fair value | 232 |
Total securities available for sale, fair value | 232 | 228
Held-to-maturity, amortized cost | 100 |
Amortized Cost | 100 | 126
Held-to-maturity, fair value | 104 |
Held-to-maturity, fair value, net | $ 104 | $ 126

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