OTHER COMPREHENSIVE INCOME (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2019 USD ($)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	$ 4,608
Other comprehensive (loss) income before reclassifications	35
Amounts reclassified from AOCI	(1)
Net current period other comprehensive (loss) income	34
Balance at end of period	4,753
Unrealized Net Losses on Debt Securities Available for Sale [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(46)
Other comprehensive (loss) income before reclassifications	54
Amounts reclassified from AOCI	0
Net current period other comprehensive (loss) income	54
Balance at end of period	8
Unrealized Net Gains (Losses) on Derivative Instruments [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	1
Other comprehensive (loss) income before reclassifications	(20)
Amounts reclassified from AOCI	(1)
Net current period other comprehensive (loss) income	(21)
Balance at end of period	(20)
Unrecognized Pension and Postretirement Obligations [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(61)
Other comprehensive (loss) income before reclassifications	1
Amounts reclassified from AOCI	0
Net current period other comprehensive (loss) income	1
Balance at end of period	(60)
Accumulated Other Comprehensive Income (Loss) [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(106)
Balance at end of period	$ (72)