INVESTMENT SECURITIES - Contractual Maturities, Available for Sale (Detail) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Amortized Cost
Due within one year	$ 501
Due after one year through five years	2,999
Due after five years through ten years	2,555
Due after ten years	3,144
Mortgage and asset-backed securities	1,969
Amortized Cost	11,168	$ 9,826
Fair Value
Due within one year	502
Due after one year through five years	3,014
Due after five years through ten years	2,561
Due after ten years	3,305
Mortgage and asset-backed securities	1,956
Fair Value	$ 11,338	$ 9,798