INVESTMENT SECURITIES - Contractual Maturities of Debt Securities Available for Sale (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Amortized Cost
Due within one year	$ 829
Due after one year through five years	2,514
Due after five years through ten years	1,655
Due after ten years	535
Mortgage and asset-backed securities	4,773
Amortized Cost	10,306	$ 10,641
Fair Value
Due within one year	828
Due after one year through five years	2,511
Due after five years through ten years	1,652
Due after ten years	540
Mortgage and asset-backed securities	4,767
Fair Value	$ 10,298	$ 10,437

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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