INVESTMENTS (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Available-for-sale Securities, Debt Maturities
Total amortized cost	$ 274,844		$ 281,290
Total fair value	276,860		283,753
Minimum contractual maturities of investments with no stated maturities, included as contractual maturities	10 years
Available-for-sale Securities transferred from Held-to-maturity
Carrying value of securities reclassified as available-for-sale	602	39
Other-than-temporary impairment loss recorded for available-for-sale investments transferred from held-to-maturity	94	13
Carrying value of held-to-maturity investments sold	167	967
Loss realized on sale of held to maturity securities	10	144
Interest and dividends on investments
Taxable interest	1,510	1,660
Interest exempt from U.S. federal income tax	172	174
Dividends	120	76
Total interest and dividends	1,802	1,910
Gross realized investments losses, excluding losses from other-than-temporary impairment
Gross realized investment gains	494	2,166
Gross realized investment losses	(44)	(241)
Net realized gains (losses)	450	1,925
Mortgage-backed securities
Available-for-sale Securities, Debt Maturities
Due within 1 year, amortized cost	2		10
After 1 but within 5 years, amortized cost	371		365
After 5 but within 10 years, amortized cost	2,044		1,992
After 10 years, amortized cost	54,463		51,598
Total amortized cost	56,880		53,965
Fair value, due within 1 year	2		10
Fair value, after 1 but within 5 years	380		374
Fair value, after 5 but within 10 years	2,159		2,124
Fair value, after 10 years	55,611		52,963
Total fair value	58,152		55,471
U.S. Treasury and federal agency securities
Available-for-sale Securities, Debt Maturities
Due within 1 year, amortized cost	7,776		9,492
After 1 but within 5 years, amortized cost	74,132		75,967
After 5 but within 10 years, amortized cost	1,914		2,171
After 10 years, amortized cost	2,854		2,670
Total amortized cost	86,676		90,300
Fair value, due within 1 year	7,797		9,499
Fair value, after 1 but within 5 years	75,248		77,267
Fair value, after 5 but within 10 years	2,123		2,408
Fair value, after 10 years	2,748		2,667
Total fair value	87,916		91,841
State and municipal securities
Available-for-sale Securities, Debt Maturities
Due within 1 year, amortized cost	298		208
After 1 but within 5 years, amortized cost	3,212		3,221
After 5 but within 10 years, amortized cost	161		155
After 10 years, amortized cost	16,477		16,436
Total amortized cost	20,148		20,020
Fair value, due within 1 year	298		208
Fair value, after 1 but within 5 years	3,214		3,223
Fair value, after 5 but within 10 years	172		165
Fair value, after 10 years	14,962		14,736
Total fair value	18,646		18,332
Foreign government
Available-for-sale Securities, Debt Maturities
Due within 1 year, amortized cost	29,868		34,873
After 1 but within 5 years, amortized cost	46,588		49,548
After 5 but within 10 years, amortized cost	8,585		7,239
After 10 years, amortized cost	1,422		1,599
Total amortized cost	86,463		93,259
Fair value, due within 1 year	29,852		34,869
Fair value, after 1 but within 5 years	46,918		49,933
Fair value, after 5 but within 10 years	8,725		7,380
Fair value, after 10 years	1,627		1,865
Total fair value	87,122		94,047
All other
Available-for-sale Securities, Debt Maturities
Due within 1 year, amortized cost	998		1,001
After 1 but within 5 years, amortized cost	11,808		11,285
After 5 but within 10 years, amortized cost	4,278		4,330
After 10 years, amortized cost	7,593		7,130
Total amortized cost	24,677		23,746
Fair value, due within 1 year	1,001		1,009
Fair value, after 1 but within 5 years	11,906		11,351
Fair value, after 5 but within 10 years	4,443		4,505
Fair value, after 10 years	7,674		7,197
Total fair value	$ 25,024		$ 24,062