FAIR VALUE MEASUREMENTS - Carrying Values and Estimated Fair Values of Financial Instruments (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Assets:
Equity securities	$ 25	$ 25
Liabilities:
Obligation to Japanese policyholder protection corporation	47	71
Investments other than Consolidated Variable Interest Entities
Assets:
Perpetual securities	4,159	5,149
Variable Interest Entity, Consolidated
Assets:
Perpetual securities	1,193	1,290
Interest rate, foreign currency, and credit default swaps	271	375
Carrying Value
Assets:
Equity securities	25	25
Interest rate, foreign currency, and credit default swaps	318	375
Liabilities:
Notes payable (excluding capitalized leases)	3,955	3,275
Interest rate, foreign currency, and credit default swaps	428	531
Obligation to Japanese policyholder protection corporation	47	71
Carrying Value | Investments other than Consolidated Variable Interest Entities
Assets:
Fixed-maturity securities	89,502	88,588
Perpetual securities	4,159	5,149
Carrying Value | Variable Interest Entity, Consolidated
Assets:
Fixed-maturity securities	5,854	5,993
Perpetual securities	1,193	1,290
Fair Value
Assets:
Equity securities	25	25
Interest rate, foreign currency, and credit default swaps	318	375
Liabilities:
Notes payable (excluding capitalized leases)	4,354	3,536
Interest rate, foreign currency, and credit default swaps	428	531
Obligation to Japanese policyholder protection corporation	47	71
Fair Value | Investments other than Consolidated Variable Interest Entities
Assets:
Fixed-maturity securities	89,219	88,039
Perpetual securities	4,159	5,149
Fair Value | Variable Interest Entity, Consolidated
Assets:
Fixed-maturity securities	5,747	5,916
Perpetual securities	$ 1,193	$ 1,290