INVESTMENTS - Fair Value of AFS Securities (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Available for Sale Securities Continuous Unrealized Loss Position
Fair value of available for sale securities that have been in an unrealized loss position for less than twelve months	$ 55,507	$ 74,026
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for less than twelve months	646	404
Fair value of available for sale securities that have been in an unrealized loss position for twelve months or longer	16,040	24,821
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for twelve months or longer	1,203	1,361
Total fair value of available for sale securities that have been in an unrealized loss position	71,547	98,847
Total gross unrealized losses of available for sale securities that have been in an unrealized loss position	1,849	1,765
Mortgage-backed securities - U.S. agency-sponsored
Available for Sale Securities Continuous Unrealized Loss Position
Fair value of available for sale securities that have been in an unrealized loss position for less than twelve months	6,254	4,198
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for less than twelve months	26	30
Fair value of available for sale securities that have been in an unrealized loss position for twelve months or longer	2,034	5,547
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for twelve months or longer	73	129
Total fair value of available for sale securities that have been in an unrealized loss position	8,288	9,745
Total gross unrealized losses of available for sale securities that have been in an unrealized loss position	99	159
Mortgage-backed securities - Prime
Available for Sale Securities Continuous Unrealized Loss Position
Fair value of available for sale securities that have been in an unrealized loss position for less than twelve months	1	5
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for less than twelve months	0	0
Fair value of available for sale securities that have been in an unrealized loss position for twelve months or longer	1	2
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for twelve months or longer	0	0
Total fair value of available for sale securities that have been in an unrealized loss position	2	7
Total gross unrealized losses of available for sale securities that have been in an unrealized loss position	0	0
Mortgage-backed securities - Non-U.S. residential
Available for Sale Securities Continuous Unrealized Loss Position
Fair value of available for sale securities that have been in an unrealized loss position for less than twelve months	2,951	1,276
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for less than twelve months	11	3
Fair value of available for sale securities that have been in an unrealized loss position for twelve months or longer	379	199
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for twelve months or longer	3	4
Total fair value of available for sale securities that have been in an unrealized loss position	3,330	1,475
Total gross unrealized losses of available for sale securities that have been in an unrealized loss position	14	7
Mortgage-backed securities - Commercial
Available for Sale Securities Continuous Unrealized Loss Position
Fair value of available for sale securities that have been in an unrealized loss position for less than twelve months	91	124
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for less than twelve months	0	1
Fair value of available for sale securities that have been in an unrealized loss position for twelve months or longer	54	136
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for twelve months or longer	1	2
Total fair value of available for sale securities that have been in an unrealized loss position	145	260
Total gross unrealized losses of available for sale securities that have been in an unrealized loss position	1	3
Mortgage-backed securities
Available for Sale Securities Continuous Unrealized Loss Position
Fair value of available for sale securities that have been in an unrealized loss position for less than twelve months	9,297	5,603
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for less than twelve months	37	34
Fair value of available for sale securities that have been in an unrealized loss position for twelve months or longer	2,468	5,884
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for twelve months or longer	77	135
Total fair value of available for sale securities that have been in an unrealized loss position	11,765	11,487
Total gross unrealized losses of available for sale securities that have been in an unrealized loss position	114	169
U.S. Treasury
Available for Sale Securities Continuous Unrealized Loss Position
Fair value of available for sale securities that have been in an unrealized loss position for less than twelve months	7,330	36,581
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for less than twelve months	116	119
Fair value of available for sale securities that have been in an unrealized loss position for twelve months or longer	339	1,013
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for twelve months or longer	1	8
Total fair value of available for sale securities that have been in an unrealized loss position	7,669	37,594
Total gross unrealized losses of available for sale securities that have been in an unrealized loss position	117	127
Agency obligations
Available for Sale Securities Continuous Unrealized Loss Position
Fair value of available for sale securities that have been in an unrealized loss position for less than twelve months	281	5,698
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for less than twelve months	5	9
Fair value of available for sale securities that have been in an unrealized loss position for twelve months or longer	49	754
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for twelve months or longer	1	4
Total fair value of available for sale securities that have been in an unrealized loss position	330	6,452
Total gross unrealized losses of available for sale securities that have been in an unrealized loss position	6	13
U.S. Treasury and federal agency securities
Available for Sale Securities Continuous Unrealized Loss Position
Fair value of available for sale securities that have been in an unrealized loss position for less than twelve months	7,611	42,279
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for less than twelve months	121	128
Fair value of available for sale securities that have been in an unrealized loss position for twelve months or longer	388	1,767
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for twelve months or longer	2	12
Total fair value of available for sale securities that have been in an unrealized loss position	7,999	44,046
Total gross unrealized losses of available for sale securities that have been in an unrealized loss position	123	140
State and municipal securities
Available for Sale Securities Continuous Unrealized Loss Position
Fair value of available for sale securities that have been in an unrealized loss position for less than twelve months	118	386
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for less than twelve months	8	15
Fair value of available for sale securities that have been in an unrealized loss position for twelve months or longer	4,905	5,802
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for twelve months or longer	889	962
Total fair value of available for sale securities that have been in an unrealized loss position	5,023	6,188
Total gross unrealized losses of available for sale securities that have been in an unrealized loss position	897	977
Foreign government
Available for Sale Securities Continuous Unrealized Loss Position
Fair value of available for sale securities that have been in an unrealized loss position for less than twelve months	29,157	18,495
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for less than twelve months	351	147
Fair value of available for sale securities that have been in an unrealized loss position for twelve months or longer	3,806	5,984
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for twelve months or longer	143	139
Total fair value of available for sale securities that have been in an unrealized loss position	32,963	24,479
Total gross unrealized losses of available for sale securities that have been in an unrealized loss position	494	286
Corporate
Available for Sale Securities Continuous Unrealized Loss Position
Fair value of available for sale securities that have been in an unrealized loss position for less than twelve months	3,869	3,511
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for less than twelve months	75	63
Fair value of available for sale securities that have been in an unrealized loss position for twelve months or longer	1,776	1,350
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for twelve months or longer	34	28
Total fair value of available for sale securities that have been in an unrealized loss position	5,645	4,861
Total gross unrealized losses of available for sale securities that have been in an unrealized loss position	109	91
Asset-backed securities
Available for Sale Securities Continuous Unrealized Loss Position
Fair value of available for sale securities that have been in an unrealized loss position for less than twelve months	5,351	3,701
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for less than twelve months	50	13
Fair value of available for sale securities that have been in an unrealized loss position for twelve months or longer	2,470	3,816
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for twelve months or longer	28	45
Total fair value of available for sale securities that have been in an unrealized loss position	7,821	7,517
Total gross unrealized losses of available for sale securities that have been in an unrealized loss position	78	58
Equity securities
Available for Sale Securities Continuous Unrealized Loss Position
Fair value of available for sale securities that have been in an unrealized loss position for less than twelve months	104	51
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for less than twelve months	4	4
Fair value of available for sale securities that have been in an unrealized loss position for twelve months or longer	227	218
Gross unrealized losses of available for sale securities that have been in an unrealized loss position for twelve months or longer	30	40
Total fair value of available for sale securities that have been in an unrealized loss position	331	269
Total gross unrealized losses of available for sale securities that have been in an unrealized loss position	$ 34	$ 44