FAIR VALUE MEASUREMENTS - Carrying Values and Estimated Fair Values of Financial Instruments (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Assets:
Equity securities	$ 23	$ 25
Liabilities:
Obligation to Japanese policyholder protection corporation	48	71
Investments Other Than Consolidated Variable Interest Entities
Assets:
Perpetual securities	3,966	5,149
Variable Interest Entity, Consolidated
Assets:
Perpetual securities	766	1,290
Interest rate, foreign currency, and credit default swaps	281	375
Carrying Value
Assets:
Equity securities	23	25
Interest rate, foreign currency, and credit default swaps	306	375
Liabilities:
Notes payable (excluding capitalized leases)	3,663	3,275
Interest rate, foreign currency, and credit default swaps	482	531
Obligation to Japanese policyholder protection corporation	48	71
Carrying Value | Investments Other Than Consolidated Variable Interest Entities
Assets:
Fixed-maturity securities	96,134	88,588
Perpetual securities	3,966	5,149
Carrying Value | Variable Interest Entity, Consolidated
Assets:
Fixed-maturity securities	6,060	5,993
Perpetual securities	766	1,290
Fair Value
Assets:
Equity securities	23	25
Interest rate, foreign currency, and credit default swaps	306	375
Liabilities:
Notes payable (excluding capitalized leases)	4,138	3,536
Interest rate, foreign currency, and credit default swaps	482	531
Obligation to Japanese policyholder protection corporation	48	71
Fair Value | Investments Other Than Consolidated Variable Interest Entities
Assets:
Fixed-maturity securities	96,265	88,039
Perpetual securities	3,966	5,149
Fair Value | Variable Interest Entity, Consolidated
Assets:
Fixed-maturity securities	6,056	5,916
Perpetual securities	$ 766	$ 1,290