INVESTMENTS - Held-to-Maturity Investments in Debt Securities (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	$ 41,134	$ 44,415
Gross Unrealized Gains	3,099	2,041
Gross Unrealized Losses	275	610
Fair Value	43,958	45,846
Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	41,134	44,415
Fair Value	43,958	45,846
Yen-denominated | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	41,134	44,415
Gross Unrealized Gains	3,099	2,041
Gross Unrealized Losses	275	610
Fair Value	43,958	45,846
Japan government and agencies | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	23,819	27,362
Fair Value	25,823	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	23,819	27,362
Gross Unrealized Gains	2,004	1,347
Gross Unrealized Losses	0	1
Fair Value	25,823	28,708
Municipalities | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	413	399
Fair Value	468	440
Municipalities | Yen-denominated | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	413	399
Gross Unrealized Gains	55	41
Gross Unrealized Losses	0	0
Fair Value	468	440
Mortgage- and asset-backed securities | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	57	58
Fair Value	60	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	57	58
Gross Unrealized Gains	3	3
Gross Unrealized Losses	0	0
Fair Value	60	61
Public Utilities | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	4,054	3,900
Fair Value	4,279	3,928
Public Utilities | Yen-denominated | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	4,054	3,900
Gross Unrealized Gains	283	150
Gross Unrealized Losses	58	122
Fair Value	4,279	3,928
Sovereign and supranational | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	3,057	2,941
Fair Value	3,275	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	3,057	2,941
Gross Unrealized Gains	246	171
Gross Unrealized Losses	28	72
Fair Value	3,275	3,040
Banks/financial Institutions | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	6,152	6,310
Fair Value	6,184	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	6,152	6,310
Gross Unrealized Gains	209	146
Gross Unrealized Losses	177	328
Fair Value	6,184	6,128
Other Corporate | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	3,582	3,445
Fair Value	3,869	3,541
Other Corporate | Yen-denominated | Fixed Maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	3,582	3,445
Gross Unrealized Gains	299	183
Gross Unrealized Losses	12	87
Fair Value	$ 3,869	$ 3,541