SECURITIES - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Credit impairments recognized in earnings	$ 2,000,000	$ 1,000,000	$ 5,000,000	$ 7,000,000
Impaired debt securities sold	0	0	0	0
Pretax non-credit related losses were deferred in OCI			41,000,000	35,000,000
Mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Value of held-to-maturity security sold	73,000,000		73,000,000
Gain recognized on sale of held-to-maturity security	2,000,000
Available-for-sale Securities
Schedule of Available-for-sale Securities [Line Items]
Cumulative credit losses recognized in earnings	63,000,000	60,000,000	63,000,000	60,000,000	$ 62,000,000	$ 62,000,000	$ 60,000,000	$ 56,000,000
Credit impairments recognized in earnings	2,000,000	1,000,000	5,000,000	7,000,000
Reductions due to increases in cash flow expectations on impaired securities	1,000,000	1,000,000	4,000,000	3,000,000
Held-to-maturity Securities
Schedule of Available-for-sale Securities [Line Items]
Cumulative credit losses recognized in earnings	$ 0	$ 0	$ 0	$ 0