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, 2012	Dec. 31, 2011
Liabilities:
Notes payable (excluding capital leases)	$ 4,138	$ 3,536
Obligation to Japanese policyholder protection corporation	48	71
Liabilities Fair Value Disclosure Financial Instruments Carried At Cost	4,186	3,607
Fixed Maturities
Assets:
Held-to-maturity securities	52,540	46,383
Carrying Value
Liabilities:
Obligation to Japanese policyholder protection corporation	48	71
Government and Agencies Debt Securities | Fixed Maturities
Assets:
Held-to-maturity securities	27,527	19,071
Municipalities | Fixed Maturities
Assets:
Held-to-maturity securities	574	584
Mortgage- and asset-backed Securities | Fixed Maturities
Assets:
Held-to-maturity securities	120	134
Public Utilities | Fixed Maturities
Assets:
Held-to-maturity securities	5,426	5,637
Sovereign and Supranational | Fixed Maturities
Assets:
Held-to-maturity securities	3,698	4,165
Banks/financial Institutions | Fixed Maturities
Assets:
Held-to-maturity securities	10,332	11,480
Other Corporate | Fixed Maturities
Assets:
Held-to-maturity securities	4,863	5,312
Level 1
Liabilities:
Notes payable (excluding capital leases)	0	0
Obligation to Japanese policyholder protection corporation	0	0
Liabilities Fair Value Disclosure Financial Instruments Carried At Cost	0	0
Level 1 | Fixed Maturities
Assets:
Held-to-maturity securities	27,527	19,071
Level 1 | Government and Agencies Debt Securities | Fixed Maturities
Assets:
Held-to-maturity securities	27,527	19,071
Level 1 | Municipalities | Fixed Maturities
Assets:
Held-to-maturity securities	0	0
Level 1 | Mortgage- and asset-backed Securities | Fixed Maturities
Assets:
Held-to-maturity securities	0	0
Level 1 | Public Utilities | Fixed Maturities
Assets:
Held-to-maturity securities	0	0
Level 1 | Sovereign and Supranational | Fixed Maturities
Assets:
Held-to-maturity securities	0	0
Level 1 | Banks/financial Institutions | Fixed Maturities
Assets:
Held-to-maturity securities	0	0
Level 1 | Other Corporate | Fixed Maturities
Assets:
Held-to-maturity securities	0	0
Level 2
Liabilities:
Notes payable (excluding capital leases)	0	0
Obligation to Japanese policyholder protection corporation	0	0
Liabilities Fair Value Disclosure Financial Instruments Carried At Cost	0	0
Level 2 | Fixed Maturities
Assets:
Held-to-maturity securities	24,928	27,217
Level 2 | Government and Agencies Debt Securities | Fixed Maturities
Assets:
Held-to-maturity securities	0	0
Level 2 | Municipalities | Fixed Maturities
Assets:
Held-to-maturity securities	574	584
Level 2 | Mortgage- and asset-backed Securities | Fixed Maturities
Assets:
Held-to-maturity securities	35	39
Level 2 | Public Utilities | Fixed Maturities
Assets:
Held-to-maturity securities	5,426	5,637
Level 2 | Sovereign and Supranational | Fixed Maturities
Assets:
Held-to-maturity securities	3,698	4,165
Level 2 | Banks/financial Institutions | Fixed Maturities
Assets:
Held-to-maturity securities	10,332	11,480
Level 2 | Other Corporate | Fixed Maturities
Assets:
Held-to-maturity securities	4,863	5,312
Level 3
Liabilities:
Notes payable (excluding capital leases)	4,138	3,536
Obligation to Japanese policyholder protection corporation	48	71
Liabilities Fair Value Disclosure Financial Instruments Carried At Cost	4,186	3,607
Level 3 | Fixed Maturities
Assets:
Held-to-maturity securities	85	95
Level 3 | Government and Agencies Debt Securities | Fixed Maturities
Assets:
Held-to-maturity securities	0	0
Level 3 | Municipalities | Fixed Maturities
Assets:
Held-to-maturity securities	0	0
Level 3 | Mortgage- and asset-backed Securities | Fixed Maturities
Assets:
Held-to-maturity securities	85	95
Level 3 | Public Utilities | Fixed Maturities
Assets:
Held-to-maturity securities	0	0
Level 3 | Sovereign and Supranational | Fixed Maturities
Assets:
Held-to-maturity securities	0	0
Level 3 | Banks/financial Institutions | Fixed Maturities
Assets:
Held-to-maturity securities	0	0
Level 3 | Other Corporate | Fixed Maturities
Assets:
Held-to-maturity securities	$ 0	$ 0