INVESTMENTS - Available-For-Sale Investments in Debt Securities, Perpetual Securities and Equity Securities (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	$ 59,722	$ 57,646
Gross Unrealized Gains	2,867	4,716
Gross Unrealized Losses	2,703	784
Fair Value	59,886	61,578
Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	56,411	53,413
Gross Unrealized Gains	2,732	4,453
Gross Unrealized Losses	2,220	613
Fair Value	56,923	57,253
Perpetual Securities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	3,293	4,213
Gross Unrealized Gains	130	259
Gross Unrealized Losses	482	170
Fair Value	2,941	4,302
Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	18	20
Gross Unrealized Gains	5	4
Gross Unrealized Losses	1	1
Fair Value	22	23
Yen Denominated | Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	24,495	27,481
Gross Unrealized Gains	959	1,050
Gross Unrealized Losses	669	487
Fair Value	24,785	28,044
Dollar Denominated | Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	31,916	25,932
Gross Unrealized Gains	1,773	3,403
Gross Unrealized Losses	1,551	126
Fair Value	32,138	29,209
Japan government and agencies | Yen Denominated | Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	12,744	12,612
Gross Unrealized Gains	445	349
Gross Unrealized Losses	22	81
Fair Value	13,167	12,880
Mortgage- and asset-backed Securities | Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Fair Value	832	1,031
Mortgage- and asset-backed Securities | Yen Denominated | Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	614	746
Gross Unrealized Gains	34	40
Gross Unrealized Losses	0	1
Fair Value	648	785
Mortgage- and asset-backed Securities | Dollar Denominated | Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	167	188
Gross Unrealized Gains	17	58
Gross Unrealized Losses	0	0
Fair Value	184	246
Public Utilities | Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Fair Value	8,015	8,497
Public Utilities | Yen Denominated | Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	2,816	3,608
Gross Unrealized Gains	96	116
Gross Unrealized Losses	78	72
Fair Value	2,834	3,652
Public Utilities | Dollar Denominated | Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	5,018	4,204
Gross Unrealized Gains	369	658
Gross Unrealized Losses	206	17
Fair Value	5,181	4,845
Sovereign and Supranational | Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Fair Value	1,680	2,072
Sovereign and Supranational | Yen Denominated | Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	1,055	1,404
Gross Unrealized Gains	82	71
Gross Unrealized Losses	0	0
Fair Value	1,137	1,475
Sovereign and Supranational | Dollar Denominated | Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	462	476
Gross Unrealized Gains	82	123
Gross Unrealized Losses	1	2
Fair Value	543	597
Banks/financial Institutions | Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Fair Value	6,737	7,634
Banks/financial Institutions | Perpetual Securities
Schedule of Available-for-sale Securities [Line Items]
Fair Value	2,732	3,950
Banks/financial Institutions | Yen Denominated | Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	3,088	3,455
Gross Unrealized Gains	163	233
Gross Unrealized Losses	322	180
Fair Value	2,929	3,508
Banks/financial Institutions | Yen Denominated | Perpetual Securities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	2,811	3,635
Gross Unrealized Gains	108	193
Gross Unrealized Losses	403	161
Fair Value	2,516	3,667
Banks/financial Institutions | Dollar Denominated | Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	3,527	3,626
Gross Unrealized Gains	329	506
Gross Unrealized Losses	48	6
Fair Value	3,808	4,126
Banks/financial Institutions | Dollar Denominated | Perpetual Securities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	208	269
Gross Unrealized Gains	22	23
Gross Unrealized Losses	14	9
Fair Value	216	283
Other Corporate | Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Fair Value	25,336	23,827
Other Corporate | Perpetual Securities
Schedule of Available-for-sale Securities [Line Items]
Fair Value	209	352
Other Corporate | Yen Denominated | Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	4,178	5,656
Gross Unrealized Gains	139	241
Gross Unrealized Losses	247	153
Fair Value	4,070	5,744
Other Corporate | Yen Denominated | Perpetual Securities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	274	309
Gross Unrealized Gains	0	43
Gross Unrealized Losses	65	0
Fair Value	209	352
Other Corporate | Dollar Denominated | Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	21,633	16,300
Gross Unrealized Gains	911	1,878
Gross Unrealized Losses	1,278	95
Fair Value	21,266	18,083
U.S. Government and Agencies | Dollar Denominated | Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	93	93
Gross Unrealized Gains	9	24
Gross Unrealized Losses	3	0
Fair Value	99	117
Municipalities | Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Fair Value	1,057	1,195
Municipalities | Dollar Denominated | Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	1,016	1,045
Gross Unrealized Gains	56	156
Gross Unrealized Losses	15	6
Fair Value	$ 1,057	$ 1,195