INVESTMENTS - Held-to-Maturity Investments in Debt Securities (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	$ 37,743	$ 44,415
Gross Unrealized Gains	3,183	2,041
Gross Unrealized Losses	210	610
Fair Value	40,716	45,846
Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	37,743	44,415
Fair Value	40,716	45,846
Yen-denominated | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	37,743	44,415
Gross Unrealized Gains	3,183	2,041
Gross Unrealized Losses	210	610
Fair Value	40,716	45,846
Japan government and agencies | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	22,056	27,362
Fair Value	24,199	28,708
Japan government and agencies | Yen-denominated | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	22,056	27,362
Gross Unrealized Gains	2,143	1,347
Gross Unrealized Losses	0	1
Fair Value	24,199	28,708
Municipalities | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	382	399
Fair Value	438	440
Municipalities | Yen-denominated | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	382	399
Gross Unrealized Gains	56	41
Gross Unrealized Losses	0	0
Fair Value	438	440
Mortgage- and asset-backed securities | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	51	58
Fair Value	54	61
Mortgage- and asset-backed securities | Yen-denominated | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	51	58
Gross Unrealized Gains	3	3
Gross Unrealized Losses	0	0
Fair Value	54	61
Public Utilities | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	3,681	3,900
Fair Value	3,903	3,928
Public Utilities | Yen-denominated | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	3,681	3,900
Gross Unrealized Gains	266	150
Gross Unrealized Losses	44	122
Fair Value	3,903	3,928
Sovereign and supranational | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	2,823	2,941
Fair Value	3,029	3,040
Sovereign and supranational | Yen-denominated | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	2,823	2,941
Gross Unrealized Gains	228	171
Gross Unrealized Losses	22	72
Fair Value	3,029	3,040
Banks/financial Institutions | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	5,432	6,310
Fair Value	5,511	6,128
Banks/financial Institutions | Yen-denominated | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	5,432	6,310
Gross Unrealized Gains	207	146
Gross Unrealized Losses	128	328
Fair Value	5,511	6,128
Other Corporate | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	3,318	3,445
Fair Value	3,582	3,541
Other Corporate | Yen-denominated | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	3,318	3,445
Gross Unrealized Gains	280	183
Gross Unrealized Losses	16	87
Fair Value	$ 3,582	$ 3,541