INVESTMENTS - Fair Value and Gross Unrealized Losses for Securities That Have Been in Continuous Unrealized Loss Position (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	$ 21,649	$ 36,214
Total Unrealized Losses	1,277	2,746
Less than 12 months Fair Value	2,728	27,790
Less than 12 months Unrealized Losses	47	1,376
12 months or longer Fair Value	18,921	8,424
12 months or longer Unrealized Losses	1,230	1,370
Fixed Maturities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	20,347	34,828
Total Unrealized Losses	1,096	2,519
Less than 12 months Fair Value	2,657	26,985
Less than 12 months Unrealized Losses	46	1,293
12 months or longer Fair Value	17,690	7,843
12 months or longer Unrealized Losses	1,050	1,226
Perpetual securities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	1,302	1,381
Total Unrealized Losses	181	226
Less than 12 months Fair Value	71	800
Less than 12 months Unrealized Losses	1	82
12 months or longer Fair Value	1,231	581
12 months or longer Unrealized Losses	180	144
Equity securities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value		5
Total Unrealized Losses		1
Less than 12 months Fair Value		5
Less than 12 months Unrealized Losses		1
12 months or longer Fair Value		0
12 months or longer Unrealized Losses		0
Yen-denominated | Fixed Maturities | Japan government and agencies
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	273	8,869
Total Unrealized Losses	1	34
Less than 12 months Fair Value	273	8,869
Less than 12 months Unrealized Losses	1	34
12 months or longer Fair Value	0	0
12 months or longer Unrealized Losses	0	0
Yen-denominated | Fixed Maturities | Public Utilities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	1,837	2,519
Total Unrealized Losses	66	140
Less than 12 months Fair Value	696	1,816
Less than 12 months Unrealized Losses	23	54
12 months or longer Fair Value	1,141	703
12 months or longer Unrealized Losses	43	86
Yen-denominated | Fixed Maturities | Sovereign and supranational
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	416	1,152
Total Unrealized Losses	28	100
Less than 12 months Fair Value	0	791
Less than 12 months Unrealized Losses	0	34
12 months or longer Fair Value	416	361
12 months or longer Unrealized Losses	28	66
Yen-denominated | Fixed Maturities | Banks/financial Institutions
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	3,364	4,533
Total Unrealized Losses	364	570
Less than 12 months Fair Value	388	2,322
Less than 12 months Unrealized Losses	6	107
12 months or longer Fair Value	2,976	2,211
12 months or longer Unrealized Losses	358	463
Yen-denominated | Fixed Maturities | Other Corporate
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	2,043	3,372
Total Unrealized Losses	127	272
Less than 12 months Fair Value	146	2,296
Less than 12 months Unrealized Losses	2	152
12 months or longer Fair Value	1,897	1,076
12 months or longer Unrealized Losses	125	120
Yen-denominated | Perpetual securities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	1,295	1,322
Total Unrealized Losses	180	217
Less than 12 months Fair Value	71	748
Less than 12 months Unrealized Losses	1	74
12 months or longer Fair Value	1,224	574
12 months or longer Unrealized Losses	179	143
Dollar-denominated | Fixed Maturities | Municipalities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	33	177
Total Unrealized Losses	3	12
Less than 12 months Fair Value	0	145
Less than 12 months Unrealized Losses	0	8
12 months or longer Fair Value	33	32
12 months or longer Unrealized Losses	3	4
Dollar-denominated | Fixed Maturities | Public Utilities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	1,512	2,023
Total Unrealized Losses	57	183
Less than 12 months Fair Value	133	1,740
Less than 12 months Unrealized Losses	1	143
12 months or longer Fair Value	1,379	283
12 months or longer Unrealized Losses	56	40
Dollar-denominated | Fixed Maturities | Sovereign and supranational
Investments, Unrealized Loss Position [Line Items]
Total Fair Value		12
Total Unrealized Losses		1
Less than 12 months Fair Value		12
Less than 12 months Unrealized Losses		1
12 months or longer Fair Value		0
12 months or longer Unrealized Losses		0
Dollar-denominated | Fixed Maturities | Banks/financial Institutions
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	329	547
Total Unrealized Losses	9	33
Less than 12 months Fair Value	51	454
Less than 12 months Unrealized Losses	0	23
12 months or longer Fair Value	278	93
12 months or longer Unrealized Losses	9	10
Dollar-denominated | Fixed Maturities | Other Corporate
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	10,540	11,588
Total Unrealized Losses	441	1,170
Less than 12 months Fair Value	970	8,504
Less than 12 months Unrealized Losses	13	733
12 months or longer Fair Value	9,570	3,084
12 months or longer Unrealized Losses	428	437
Dollar-denominated | Fixed Maturities | US government and agencies
Investments, Unrealized Loss Position [Line Items]
Total Fair Value		36
Total Unrealized Losses		4
Less than 12 months Fair Value		36
Less than 12 months Unrealized Losses		4
12 months or longer Fair Value		0
12 months or longer Unrealized Losses		0
Dollar-denominated | Perpetual securities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	7	59
Total Unrealized Losses	1	9
Less than 12 months Fair Value	0	52
Less than 12 months Unrealized Losses	0	8
12 months or longer Fair Value	7	7
12 months or longer Unrealized Losses	$ 1	$ 1