INVESTMENT SECURITIES - Contractual Maturities of Debt Securities Available for Sale (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Amortized Cost
Due within one year	$ 802
Due after one year through five years	2,145
Due after five years through ten years	2,247
Due after ten years	1,487
Mortgage and asset-backed securities	5,756
Amortized Cost	12,437	$ 11,160
Fair Value
Due within one year	805
Due after one year through five years	2,236
Due after five years through ten years	2,396
Due after ten years	1,553
Mortgage and asset-backed securities	5,961
Fair Value	$ 12,951	$ 11,371

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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