SECURITIES - Schedule of Cumulative Credit Losses Recognized in Earnings (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Credit impairments recognized in earnings on debt securities that have been previously impaired	$ 2	$ 2	$ 3	$ 6
Available-for-sale Securities
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Cumulative balance at beginning of period	62	59	62	56
Credit impairments recognized in earnings on debt securities that have been previously impaired	2	2	3	6
Reductions due to increases in cash flow expectations on impaired securities	(2)	(1)	(3)	(2)
Cumulative balance at end of period	$ 62	$ 60	$ 62	$ 60