OTHER COMPREHENSIVE INCOME (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2020 USD ($)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	$ 4,883
Other comprehensive (loss) income before reclassifications	32
Amounts reclassified from AOCI	7
Net current period other comprehensive (loss) income	39
Balance at end of period	4,951
Unrealized Net Gains (Losses) on Debt Securities Available for Sale [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	11
Other comprehensive (loss) income before reclassifications	63
Amounts reclassified from AOCI	0
Net current period other comprehensive (loss) income	63
Balance at end of period	74
Unrealized Net Gains (Losses) on Derivative Instruments [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(18)
Other comprehensive (loss) income before reclassifications	(32)
Amounts reclassified from AOCI	7
Net current period other comprehensive (loss) income	(25)
Balance at end of period	(43)
Unrecognized Pension and Postretirement Obligations [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(58)
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	(57)
Accumulated Other Comprehensive Income (Loss) [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(65)
Balance at end of period	$ (26)