RECLASSIFICATIONS OUT OF ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ 19,747	$ 19,646
Other-than-temporary impairment not recognized in earnings on securities	(12)	(25)
Ending balance	19,847	19,965
Total AOCI
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(668)	(387)
Other comprehensive income before reclassifications	2	187
Other-than-temporary impairment not recognized in earnings on securities	(12)	(25)
Amounts reclassified from other comprehensive (loss) income	(5)	(11)
Net other comprehensive income	(15)	151
Ending balance	(683)	(236)
Net Unrealized (Losses) Gains on Derivatives
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(88)	10
Other comprehensive income before reclassifications	(3)	33
Other-than-temporary impairment not recognized in earnings on securities	0	0
Amounts reclassified from other comprehensive (loss) income	(6)	(8)
Net other comprehensive income	(9)	25
Ending balance	(97)	35
Net Unrealized (Losses) Gains on Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(186)	(28)
Other comprehensive income before reclassifications	5	154
Other-than-temporary impairment not recognized in earnings on securities	(12)	(25)
Amounts reclassified from other comprehensive (loss) income	(2)	(5)
Net other comprehensive income	(9)	124
Ending balance	(195)	96
Employee Benefit Plans
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(394)	(369)
Other comprehensive income before reclassifications	0	0
Other-than-temporary impairment not recognized in earnings on securities	0	0
Amounts reclassified from other comprehensive (loss) income	3	2
Net other comprehensive income	3	2
Ending balance	$ (391)	$ (367)