INVESTMENTS - Debt Securities in HTM in Unrecognized Loss Position (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Held-to-maturity Securities, Continuous Unrealized Loss Position
Fair value less than 12 months	$ 2,064	$ 2,541
Gross unrecognized losses less than 12 months	41	35
Fair value 12 months or longer	6,464	1,622
Gross unrecognized losses 12 months or longer	240	326
Fair value, total	8,528	4,163
Gross unrecognized losses, total	281	361
Unrealized loss, other than temporary impairment, not credit loss, recorded in AOCI	(477)	(780)
Mortgage-backed securities
Held-to-maturity Securities, Continuous Unrealized Loss Position
Fair value less than 12 months	0	4
Gross unrecognized losses less than 12 months	0	0
Fair value 12 months or longer	2,828	1,134
Gross unrecognized losses 12 months or longer	170	294
Fair value, total	2,828	1,138
Gross unrecognized losses, total	170	294
State and municipal securities
Held-to-maturity Securities, Continuous Unrealized Loss Position
Fair value less than 12 months	1,747	2,528
Gross unrecognized losses less than 12 months	38	34
Fair value 12 months or longer	1,741	314
Gross unrecognized losses 12 months or longer	61	23
Fair value, total	3,488	2,842
Gross unrecognized losses, total	99	57
Foreign government
Held-to-maturity Securities, Continuous Unrealized Loss Position
Fair value less than 12 months	177	0
Gross unrecognized losses less than 12 months	0	0
Fair value 12 months or longer	0	0
Gross unrecognized losses 12 months or longer	0	0
Fair value, total	177	0
Gross unrecognized losses, total	0	0
Asset-backed securities
Held-to-maturity Securities, Continuous Unrealized Loss Position
Fair value less than 12 months	140	9
Gross unrecognized losses less than 12 months	3	1
Fair value 12 months or longer	1,895	174
Gross unrecognized losses 12 months or longer	9	9
Fair value, total	2,035	183
Gross unrecognized losses, total	$ 12	$ 10