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	Jun. 30, 2013	Dec. 31, 2012
Assets:
Available-for-sale Securities	$ 58,666	$ 61,578
Asset derivatives	620	345
Cash and cash equivalents	2,388	2,041
Total assets	61,674	63,964
Liabilities:
Liability derivatives	447	934
Total liabilities	447	934
Interest rate swaps
Assets:
Asset derivatives	22	32
Liabilities:
Liability derivatives	1	3
Foreign currency swaps
Assets:
Asset derivatives	381	311
Liabilities:
Liability derivatives	284	329
Foreign currency forwards
Assets:
Asset derivatives	178
Liabilities:
Liability derivatives	94	535
Foreign currency options
Assets:
Asset derivatives	37
Liabilities:
Liability derivatives	22
Credit default swaps
Assets:
Asset derivatives	2	2
Liabilities:
Liability derivatives	46	67
Fixed Maturities
Assets:
Available-for-sale Securities	55,810	57,253
Fixed Maturities | Government and Agencies Debt Securities
Assets:
Available-for-sale Securities	12,402	12,997
Fixed Maturities | Municipalities
Assets:
Available-for-sale Securities	1,091	1,195
Fixed Maturities | Mortgage- and asset-backed Securities
Assets:
Available-for-sale Securities	895	1,031
Fixed Maturities | Public Utilities
Assets:
Available-for-sale Securities	7,866	8,497
Fixed Maturities | Sovereign and Supranational
Assets:
Available-for-sale Securities	1,661	2,072
Fixed Maturities | Banks/financial Institutions
Assets:
Available-for-sale Securities	6,694	7,634
Fixed Maturities | Other Corporate
Assets:
Available-for-sale Securities	25,201	23,827
Perpetual Securities
Assets:
Available-for-sale Securities	2,834	4,302
Perpetual Securities | Banks/financial Institutions
Assets:
Available-for-sale Securities	2,631	3,950
Perpetual Securities | Other Corporate
Assets:
Available-for-sale Securities	203	352
Equity Securities
Assets:
Available-for-sale Securities	22	23
Level 1
Assets:
Available-for-sale Securities	11,769	12,278
Asset derivatives	0	0
Cash and cash equivalents	2,388	2,041
Total assets	14,157	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 | Fixed Maturities
Assets:
Available-for-sale Securities	11,755	12,265
Level 1 | Fixed Maturities | Government and Agencies Debt Securities
Assets:
Available-for-sale Securities	11,755	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	46,421	45,895
Asset derivatives	485	154
Cash and cash equivalents	0	0
Total assets	46,906	46,049
Liabilities:
Total liabilities	163	535
Level 2 | Interest rate swaps
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives	0	0
Level 2 | Foreign currency swaps
Assets:
Asset derivatives	270	154
Liabilities:
Liability derivatives	47	0
Level 2 | Foreign currency forwards
Assets:
Asset derivatives	178
Liabilities:
Liability derivatives	94	535
Level 2 | Foreign currency options
Assets:
Asset derivatives	37
Liabilities:
Liability derivatives	22
Level 2 | Credit default swaps
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives	0	0
Level 2 | Fixed Maturities
Assets:
Available-for-sale Securities	43,631	41,802
Level 2 | Fixed Maturities | Government and Agencies Debt Securities
Assets:
Available-for-sale Securities	647	732
Level 2 | Fixed Maturities | Municipalities
Assets:
Available-for-sale Securities	1,091	1,195
Level 2 | Fixed Maturities | Mortgage- and asset-backed Securities
Assets:
Available-for-sale Securities	496	693
Level 2 | Fixed Maturities | Public Utilities
Assets:
Available-for-sale Securities	7,866	8,077
Level 2 | Fixed Maturities | Sovereign and Supranational
Assets:
Available-for-sale Securities	1,661	1,654
Level 2 | Fixed Maturities | Banks/financial Institutions
Assets:
Available-for-sale Securities	6,669	6,610
Level 2 | Fixed Maturities | Other Corporate
Assets:
Available-for-sale Securities	25,201	22,841
Level 2 | Perpetual Securities
Assets:
Available-for-sale Securities	2,785	4,087
Level 2 | Perpetual Securities | Banks/financial Institutions
Assets:
Available-for-sale Securities	2,582	3,735
Level 2 | Perpetual Securities | Other Corporate
Assets:
Available-for-sale Securities	203	352
Level 2 | Equity Securities
Assets:
Available-for-sale Securities	5	6
Level 3
Assets:
Available-for-sale Securities	476	3,405
Asset derivatives	135	191
Cash and cash equivalents	0	0
Total assets	611	3,596
Liabilities:
Total liabilities	284	399
Level 3 | Interest rate swaps
Assets:
Asset derivatives	22	32
Liabilities:
Liability derivatives	1	3
Level 3 | Foreign currency swaps
Assets:
Asset derivatives	111	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	46	67
Level 3 | Fixed Maturities
Assets:
Available-for-sale Securities	424	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	399	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	25	1,024
Level 3 | Fixed Maturities | Other Corporate
Assets:
Available-for-sale Securities	0	986
Level 3 | Perpetual Securities
Assets:
Available-for-sale Securities	49	215
Level 3 | Perpetual Securities | Banks/financial Institutions
Assets:
Available-for-sale Securities	49	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