FAIR VALUE MEASUREMENTS - Fair Value Hierarchy Levels of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Assets:
Available-for-sale Securities	$ 83,315	$ 67,794
Asset derivatives	1,963	676
Other Investments	207	176
Cash and cash equivalents	3,700	4,350
Total assets	89,185	72,996
Liabilities:
Liability derivatives	542	371
Total liabilities	542	371
Foreign currency swaps
Assets:
Asset derivatives	492	563
Liabilities:
Liability derivatives	396	314
Foreign currency forwards
Assets:
Asset derivatives	1,459	107
Liabilities:
Liability derivatives	93	49
Foreign currency options
Assets:
Asset derivatives	11	5
Liabilities:
Liability derivatives	53	8
Credit default swaps
Assets:
Asset derivatives	1	1
Fixed maturities
Assets:
Available-for-sale Securities	80,286	65,349
Fixed maturities | Government and agencies
Assets:
Available-for-sale Securities	28,143	19,276
Fixed maturities | Municipalities
Assets:
Available-for-sale Securities	1,360	1,208
Fixed maturities | Mortgage- and asset-backed securities
Assets:
Available-for-sale Securities	1,138	582
Fixed maturities | Public utilities
Assets:
Available-for-sale Securities	8,327	7,479
Fixed maturities | Sovereign and supranational
Assets:
Available-for-sale Securities	1,565	1,407
Fixed maturities | Banks/financial institutions
Assets:
Available-for-sale Securities	6,226	6,019
Fixed maturities | Other corporate
Assets:
Available-for-sale Securities	33,527	29,378
Perpetual securities
Assets:
Available-for-sale Securities	1,832	1,947
Perpetual securities | Banks/financial institutions
Assets:
Available-for-sale Securities	1,598	1,742
Perpetual securities | Other corporate
Assets:
Available-for-sale Securities	234	205
Equity securities
Assets:
Available-for-sale Securities	1,197	498
Level 1
Assets:
Available-for-sale Securities	28,472	19,158
Asset derivatives	0	0
Other Investments	207	176
Cash and cash equivalents	3,700	4,350
Total assets	32,379	23,684
Liabilities:
Total liabilities	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	0
Liabilities:
Liability derivatives	0	0
Level 1 | Foreign currency options
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives	0	0
Level 1 | Credit default swaps
Assets:
Asset derivatives	0	0
Level 1 | Fixed maturities
Assets:
Available-for-sale Securities	27,284	18,669
Level 1 | Fixed maturities | Government and agencies
Assets:
Available-for-sale Securities	27,284	18,669
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	1,188	489
Level 2
Assets:
Available-for-sale Securities	54,562	48,387
Asset derivatives	1,786	574
Other Investments	0	0
Cash and cash equivalents	0	0
Total assets	56,348	48,961
Liabilities:
Total liabilities	425	78
Level 2 | Foreign currency swaps
Assets:
Asset derivatives	316	462
Liabilities:
Liability derivatives	279	21
Level 2 | Foreign currency forwards
Assets:
Asset derivatives	1,459	107
Liabilities:
Liability derivatives	93	49
Level 2 | Foreign currency options
Assets:
Asset derivatives	11	5
Liabilities:
Liability derivatives	53	8
Level 2 | Credit default swaps
Assets:
Asset derivatives	0	0
Level 2 | Fixed maturities
Assets:
Available-for-sale Securities	52,724	46,434
Level 2 | Fixed maturities | Government and agencies
Assets:
Available-for-sale Securities	859	607
Level 2 | Fixed maturities | Municipalities
Assets:
Available-for-sale Securities	1,360	1,208
Level 2 | Fixed maturities | Mortgage- and asset-backed securities
Assets:
Available-for-sale Securities	886	362
Level 2 | Fixed maturities | Public utilities
Assets:
Available-for-sale Securities	8,327	7,479
Level 2 | Fixed maturities | Sovereign and supranational
Assets:
Available-for-sale Securities	1,565	1,407
Level 2 | Fixed maturities | Banks/financial institutions
Assets:
Available-for-sale Securities	6,200	5,993
Level 2 | Fixed maturities | Other corporate
Assets:
Available-for-sale Securities	33,527	29,378
Level 2 | Perpetual securities
Assets:
Available-for-sale Securities	1,832	1,947
Level 2 | Perpetual securities | Banks/financial institutions
Assets:
Available-for-sale Securities	1,598	1,742
Level 2 | Perpetual securities | Other corporate
Assets:
Available-for-sale Securities	234	205
Level 2 | Equity securities
Assets:
Available-for-sale Securities	6	6
Level 3
Assets:
Available-for-sale Securities	281	249
Asset derivatives	177	102
Other Investments	0	0
Cash and cash equivalents	0	0
Total assets	458	351
Liabilities:
Total liabilities	117	293
Level 3 | Foreign currency swaps
Assets:
Asset derivatives	176	101
Liabilities:
Liability derivatives	117	293
Level 3 | Foreign currency forwards
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives	0	0
Level 3 | Foreign currency options
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives	0	0
Level 3 | Credit default swaps
Assets:
Asset derivatives	1	1
Level 3 | Fixed maturities
Assets:
Available-for-sale Securities	278	246
Level 3 | Fixed maturities | Government and agencies
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	252	220
Level 3 | Fixed maturities | Public utilities
Assets:
Available-for-sale Securities	0	0
Level 3 | Fixed maturities | Sovereign and supranational
Assets:
Available-for-sale Securities	0	0
Level 3 | Fixed maturities | Banks/financial institutions
Assets:
Available-for-sale Securities	26	26
Level 3 | Fixed maturities | Other corporate
Assets:
Available-for-sale Securities	0	0
Level 3 | Perpetual securities
Assets:
Available-for-sale Securities	0	0
Level 3 | Perpetual securities | Banks/financial institutions
Assets:
Available-for-sale Securities	0	0
Level 3 | Perpetual securities | Other corporate
Assets:
Available-for-sale Securities	0	0
Level 3 | Equity securities
Assets:
Available-for-sale Securities	$ 3	$ 3