FAIR VALUE MEASUREMENTS - Fair Value Hierarchy Levels of Assets and Liabilities Carried at Cost or Amortized Cost (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Assets:
Securities held to maturity, fixed maturities, amortized cost	$ 41,134	$ 44,415
Securities held to maturity, fixed maturities, fair value	43,958	45,846
Liabilities
Other policyholder funds	6,938	5,861
Other policyholders' funds fair value disclosure	6,794	5,715
Notes Payable	4,918	4,891
Notes Payable, Fair Value Disclosure	5,480	5,241
Total Financial Instrument Liabilities Not Carried At Fair Value	11,856	10,752
Liabilities Fair Value Disclosure Financial Instruments Carried At Cost	12,274	10,956
Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, amortized cost	41,134	44,415
Securities held to maturity, fixed maturities, fair value	43,958	45,846
Japan government and agencies | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, amortized cost	23,819	27,362
Securities held to maturity, fixed maturities, fair value	25,823	28,708
Municipalities | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, amortized cost	413	399
Securities held to maturity, fixed maturities, fair value	468	440
Mortgage- and asset-backed securities | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, amortized cost	57	58
Securities held to maturity, fixed maturities, fair value	60	61
Public Utilities | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, amortized cost	4,054	3,900
Securities held to maturity, fixed maturities, fair value	4,279	3,928
Sovereign and supranational | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, amortized cost	3,057	2,941
Securities held to maturity, fixed maturities, fair value	3,275	3,040
Banks/financial Institutions | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, amortized cost	6,152	6,310
Securities held to maturity, fixed maturities, fair value	6,184	6,128
Other Corporate | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, amortized cost	3,582	3,445
Securities held to maturity, fixed maturities, fair value	3,869	3,541
Level 1
Liabilities
Other policyholders' funds fair value disclosure	0	0
Notes Payable, Fair Value Disclosure	0	0
Liabilities Fair Value Disclosure Financial Instruments Carried At Cost	0	0
Level 1 | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	25,823	28,708
Level 1 | Japan government and agencies | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	25,823	28,708
Level 1 | Municipalities | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	0	0
Level 1 | Mortgage- and asset-backed securities | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	0	0
Level 1 | Public Utilities | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	0	0
Level 1 | Sovereign and supranational | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	0	0
Level 1 | Banks/financial Institutions | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	0	0
Level 1 | Other Corporate | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	0	0
Level 2
Liabilities
Other policyholders' funds fair value disclosure	0	0
Notes Payable, Fair Value Disclosure	0	0
Liabilities Fair Value Disclosure Financial Instruments Carried At Cost	0	0
Level 2 | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	18,094	17,097
Level 2 | Japan government and agencies | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	0	0
Level 2 | Municipalities | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	468	440
Level 2 | Mortgage- and asset-backed securities | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	19	20
Level 2 | Public Utilities | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	4,279	3,928
Level 2 | Sovereign and supranational | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	3,275	3,040
Level 2 | Banks/financial Institutions | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	6,184	6,128
Level 2 | Other Corporate | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	3,869	3,541
Level 3
Liabilities
Other policyholders' funds fair value disclosure	6,794	5,715
Notes Payable, Fair Value Disclosure	5,480	5,241
Liabilities Fair Value Disclosure Financial Instruments Carried At Cost	12,274	10,956
Level 3 | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	41	41
Level 3 | Japan government and agencies | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	0	0
Level 3 | Municipalities | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	0	0
Level 3 | Mortgage- and asset-backed securities | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	41	41
Level 3 | Public Utilities | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	0	0
Level 3 | Sovereign and supranational | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	0	0
Level 3 | Banks/financial Institutions | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	0	0
Level 3 | Other Corporate | Fixed Maturities
Assets:
Securities held to maturity, fixed maturities, fair value	$ 0	$ 0