FAIR VALUE MEASUREMENTS - Fair Value Hierarchy Levels of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Assets:
Available-for-sale Securities	$ 59,886	$ 61,578
Asset derivatives	598	345
Cash and cash equivalents	2,749	2,041
Total assets	63,233	63,964
Liabilities:
Liability derivatives	435	934
Total liabilities	435	934
Interest rate swaps
Assets:
Asset derivatives	1	32
Liabilities:
Liability derivatives	1	3
Foreign currency swaps
Assets:
Asset derivatives	426	311
Liabilities:
Liability derivatives	300	329
Foreign currency forwards
Assets:
Asset derivatives	129
Liabilities:
Liability derivatives	13	535
Foreign currency options
Assets:
Asset derivatives	2
Liabilities:
Liability derivatives	4
Credit default swaps
Assets:
Asset derivatives	2	2
Liabilities:
Liability derivatives	9	67
Interest rate swaptions
Assets:
Asset derivatives	38
Liabilities:
Liability derivatives	108
Fixed Maturities
Assets:
Available-for-sale Securities	56,923	57,253
Fixed Maturities | Government and Agencies Debt Securities
Assets:
Available-for-sale Securities	13,266	12,997
Fixed Maturities | Municipalities
Assets:
Available-for-sale Securities	1,057	1,195
Fixed Maturities | Mortgage- and asset-backed Securities
Assets:
Available-for-sale Securities	832	1,031
Fixed Maturities | Public Utilities
Assets:
Available-for-sale Securities	8,015	8,497
Fixed Maturities | Sovereign and Supranational
Assets:
Available-for-sale Securities	1,680	2,072
Fixed Maturities | Banks/financial Institutions
Assets:
Available-for-sale Securities	6,737	7,634
Fixed Maturities | Other Corporate
Assets:
Available-for-sale Securities	25,336	23,827
Perpetual Securities
Assets:
Available-for-sale Securities	2,941	4,302
Perpetual Securities | Banks/financial Institutions
Assets:
Available-for-sale Securities	2,732	3,950
Perpetual Securities | Other Corporate
Assets:
Available-for-sale Securities	209	352
Equity Securities
Assets:
Available-for-sale Securities	22	23
Level 1
Assets:
Available-for-sale Securities	12,623	12,278
Asset derivatives	0	0
Cash and cash equivalents	2,749	2,041
Total assets	15,372	14,319
Liabilities:
Total liabilities	0	0
Level 1 | Interest rate swaps
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives	0	0
Level 1 | Foreign currency swaps
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives	0	0
Level 1 | Foreign currency forwards
Assets:
Asset derivatives	0
Liabilities:
Liability derivatives	0	0
Level 1 | Foreign currency options
Assets:
Asset derivatives	0
Liabilities:
Liability derivatives	0
Level 1 | Credit default swaps
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives	0	0
Level 1 | Interest rate swaptions
Assets:
Asset derivatives	0
Liabilities:
Liability derivatives	0
Level 1 | Fixed Maturities
Assets:
Available-for-sale Securities	12,609	12,265
Level 1 | Fixed Maturities | Government and Agencies Debt Securities
Assets:
Available-for-sale Securities	12,609	12,265
Level 1 | Fixed Maturities | Municipalities
Assets:
Available-for-sale Securities	0	0
Level 1 | Fixed Maturities | Mortgage- and asset-backed Securities
Assets:
Available-for-sale Securities	0	0
Level 1 | Fixed Maturities | Public Utilities
Assets:
Available-for-sale Securities	0	0
Level 1 | Fixed Maturities | Sovereign and Supranational
Assets:
Available-for-sale Securities	0	0
Level 1 | Fixed Maturities | Banks/financial Institutions
Assets:
Available-for-sale Securities	0	0
Level 1 | Fixed Maturities | Other Corporate
Assets:
Available-for-sale Securities	0	0
Level 1 | Perpetual Securities
Assets:
Available-for-sale Securities	0	0
Level 1 | Perpetual Securities | Banks/financial Institutions
Assets:
Available-for-sale Securities	0	0
Level 1 | Perpetual Securities | Other Corporate
Assets:
Available-for-sale Securities	0	0
Level 1 | Equity Securities
Assets:
Available-for-sale Securities	14	13
Level 2
Assets:
Available-for-sale Securities	46,782	45,895
Asset derivatives	433	154
Cash and cash equivalents	0	0
Total assets	47,215	46,049
Liabilities:
Total liabilities	188	535
Level 2 | Interest rate swaps
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives	0	0
Level 2 | Foreign currency swaps
Assets:
Asset derivatives	264	154
Liabilities:
Liability derivatives	63	0
Level 2 | Foreign currency forwards
Assets:
Asset derivatives	129
Liabilities:
Liability derivatives	13	535
Level 2 | Foreign currency options
Assets:
Asset derivatives	2
Liabilities:
Liability derivatives	4
Level 2 | Credit default swaps
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives	0	0
Level 2 | Interest rate swaptions
Assets:
Asset derivatives	38
Liabilities:
Liability derivatives	108
Level 2 | Fixed Maturities
Assets:
Available-for-sale Securities	43,887	41,802
Level 2 | Fixed Maturities | Government and Agencies Debt Securities
Assets:
Available-for-sale Securities	657	732
Level 2 | Fixed Maturities | Municipalities
Assets:
Available-for-sale Securities	1,057	1,195
Level 2 | Fixed Maturities | Mortgage- and asset-backed Securities
Assets:
Available-for-sale Securities	429	693
Level 2 | Fixed Maturities | Public Utilities
Assets:
Available-for-sale Securities	8,015	8,077
Level 2 | Fixed Maturities | Sovereign and Supranational
Assets:
Available-for-sale Securities	1,680	1,654
Level 2 | Fixed Maturities | Banks/financial Institutions
Assets:
Available-for-sale Securities	6,713	6,610
Level 2 | Fixed Maturities | Other Corporate
Assets:
Available-for-sale Securities	25,336	22,841
Level 2 | Perpetual Securities
Assets:
Available-for-sale Securities	2,890	4,087
Level 2 | Perpetual Securities | Banks/financial Institutions
Assets:
Available-for-sale Securities	2,681	3,735
Level 2 | Perpetual Securities | Other Corporate
Assets:
Available-for-sale Securities	209	352
Level 2 | Equity Securities
Assets:
Available-for-sale Securities	5	6
Level 3
Assets:
Available-for-sale Securities	481	3,405
Asset derivatives	165	191
Cash and cash equivalents	0	0
Total assets	646	3,596
Liabilities:
Total liabilities	247	399
Level 3 | Interest rate swaps
Assets:
Asset derivatives	1	32
Liabilities:
Liability derivatives	1	3
Level 3 | Foreign currency swaps
Assets:
Asset derivatives	162	157
Liabilities:
Liability derivatives	237	329
Level 3 | Foreign currency forwards
Assets:
Asset derivatives	0
Liabilities:
Liability derivatives	0	0
Level 3 | Foreign currency options
Assets:
Asset derivatives	0
Liabilities:
Liability derivatives	0
Level 3 | Credit default swaps
Assets:
Asset derivatives	2	2
Liabilities:
Liability derivatives	9	67
Level 3 | Interest rate swaptions
Assets:
Asset derivatives	0
Liabilities:
Liability derivatives	0
Level 3 | Fixed Maturities
Assets:
Available-for-sale Securities	427	3,186
Level 3 | Fixed Maturities | Government and Agencies Debt Securities
Assets:
Available-for-sale Securities	0	0
Level 3 | Fixed Maturities | Municipalities
Assets:
Available-for-sale Securities	0	0
Level 3 | Fixed Maturities | Mortgage- and asset-backed Securities
Assets:
Available-for-sale Securities	403	338
Level 3 | Fixed Maturities | Public Utilities
Assets:
Available-for-sale Securities	0	420
Level 3 | Fixed Maturities | Sovereign and Supranational
Assets:
Available-for-sale Securities	0	418
Level 3 | Fixed Maturities | Banks/financial Institutions
Assets:
Available-for-sale Securities	24	1,024
Level 3 | Fixed Maturities | Other Corporate
Assets:
Available-for-sale Securities	0	986
Level 3 | Perpetual Securities
Assets:
Available-for-sale Securities	51	215
Level 3 | Perpetual Securities | Banks/financial Institutions
Assets:
Available-for-sale Securities	51	215
Level 3 | Perpetual Securities | Other Corporate
Assets:
Available-for-sale Securities	0	0
Level 3 | Equity Securities
Assets:
Available-for-sale Securities	$ 3	$ 4