INVESTMENTS - Held-to-Maturity Investments in Debt Securities (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Schedule of Held-to-maturity Securities [Line Items]
Cost or Amortized Cost	$ 43,607	$ 54,426
Gross Unrealized Gains	2,102	1,213
Gross Unrealized Losses	953	798
Fair Value	44,756	54,841
Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Cost or Amortized Cost	43,607	54,426
Fair Value	44,756	54,841
Yen Denominated | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Cost or Amortized Cost	43,607	54,426
Gross Unrealized Gains	2,102	1,213
Gross Unrealized Losses	953	798
Fair Value	44,756	54,841
Japan government and agencies | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Cost or Amortized Cost	24,708	32,043
Fair Value	26,074	32,332
Japan government and agencies | Yen Denominated | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Cost or Amortized Cost	24,708	32,043
Gross Unrealized Gains	1,366	356
Gross Unrealized Losses	0	67
Fair Value	26,074	32,332
Municipalities | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Cost or Amortized Cost	432	492
Fair Value	481	520
Municipalities | Yen Denominated | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Cost or Amortized Cost	432	492
Gross Unrealized Gains	49	30
Gross Unrealized Losses	0	2
Fair Value	481	520
Mortgage- and asset-backed Securities | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Cost or Amortized Cost	66	90
Fair Value	69	94
Mortgage- and asset-backed Securities | Yen Denominated | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Cost or Amortized Cost	66	90
Gross Unrealized Gains	3	4
Gross Unrealized Losses	0	0
Fair Value	69	94
Public Utilities | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Cost or Amortized Cost	4,359	4,924
Fair Value	4,343	5,051
Public Utilities | Yen Denominated | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Cost or Amortized Cost	4,359	4,924
Gross Unrealized Gains	168	233
Gross Unrealized Losses	184	106
Fair Value	4,343	5,051
Sovereign and Supranational | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Cost or Amortized Cost	3,219	3,209
Fair Value	3,275	3,317
Sovereign and Supranational | Yen Denominated | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Cost or Amortized Cost	3,219	3,209
Gross Unrealized Gains	160	192
Gross Unrealized Losses	104	84
Fair Value	3,275	3,317
Banks/financial Institutions | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Cost or Amortized Cost	6,905	9,211
Fair Value	6,555	8,991
Banks/financial Institutions | Yen Denominated | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Cost or Amortized Cost	6,905	9,211
Gross Unrealized Gains	143	211
Gross Unrealized Losses	493	431
Fair Value	6,555	8,991
Other Corporate | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Cost or Amortized Cost	3,918	4,457
Fair Value	3,959	4,536
Other Corporate | Yen Denominated | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Cost or Amortized Cost	3,918	4,457
Gross Unrealized Gains	213	187
Gross Unrealized Losses	172	108
Fair Value	$ 3,959	$ 4,536