INVESTMENT SECURITIES - Contractual Maturities of Debt Securities Available for Sale (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Amortized Cost
Due within one year	$ 543
Due after one year through five years	2,185
Due after five years through ten years	2,919
Due after ten years	1,355
Mortgage and asset-backed securities	6,923
Amortized Cost	13,925	$ 12,437
Fair Value
Due within one year	547
Due after one year through five years	2,254
Due after five years through ten years	2,966
Due after ten years	1,367
Mortgage and asset-backed securities	6,979
Fair Value	$ 14,113	$ 12,951

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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