INVESTMENT SECURITIES - Contractual Maturities of Debt Securities Available for Sale (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Amortized Cost
Due within one year	$ 1,337
Due after one year through five years	1,918
Due after five years through ten years	1,750
Due after ten years	1,020
Mortgage and asset-backed securities	5,398
Amortized Cost	11,423	$ 11,160
Fair Value
Due within one year	1,339
Due after one year through five years	1,905
Due after five years through ten years	1,736
Due after ten years	1,017
Mortgage and asset-backed securities	5,500
Fair Value	$ 11,497	$ 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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