INVESTMENTS - Fair Value and Gross Unrealized Losses for Securities That Have Been in Continuous Unrealized Loss Position (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	$ 19,636	$ 36,214
Total Unrealized Losses	1,186	2,746
Less than 12 months Fair Value	4,361	27,790
Less than 12 months Unrealized Losses	80	1,376
12 months or longer Fair Value	15,275	8,424
12 months or longer Unrealized Losses	1,106	1,370
Fixed Maturities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	18,815	34,828
Total Unrealized Losses	1,071	2,519
Less than 12 months Fair Value	4,315	26,985
Less than 12 months Unrealized Losses	80	1,293
12 months or longer Fair Value	14,500	7,843
12 months or longer Unrealized Losses	991	1,226
Perpetual securities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	821	1,381
Total Unrealized Losses	115	226
Less than 12 months Fair Value	46	800
Less than 12 months Unrealized Losses	0	82
12 months or longer Fair Value	775	581
12 months or longer Unrealized Losses	115	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		8,869
Total Unrealized Losses		34
Less than 12 months Fair Value		8,869
Less than 12 months Unrealized Losses		34
12 months or longer Fair Value		0
12 months or longer Unrealized Losses		0
Yen-denominated | Fixed Maturities | Public Utilities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	1,346	2,519
Total Unrealized Losses	50	140
Less than 12 months Fair Value	577	1,816
Less than 12 months Unrealized Losses	15	54
12 months or longer Fair Value	769	703
12 months or longer Unrealized Losses	35	86
Yen-denominated | Fixed Maturities | Sovereign and supranational
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	389	1,152
Total Unrealized Losses	22	100
Less than 12 months Fair Value	0	791
Less than 12 months Unrealized Losses	0	34
12 months or longer Fair Value	389	361
12 months or longer Unrealized Losses	22	66
Yen-denominated | Fixed Maturities | Banks/financial Institutions
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	2,881	4,533
Total Unrealized Losses	325	570
Less than 12 months Fair Value	341	2,322
Less than 12 months Unrealized Losses	7	107
12 months or longer Fair Value	2,540	2,211
12 months or longer Unrealized Losses	318	463
Yen-denominated | Fixed Maturities | Other Corporate
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	1,266	3,372
Total Unrealized Losses	123	272
Less than 12 months Fair Value	0	2,296
Less than 12 months Unrealized Losses	0	152
12 months or longer Fair Value	1,266	1,076
12 months or longer Unrealized Losses	123	120
Yen-denominated | Perpetual securities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	814	1,322
Total Unrealized Losses	114	217
Less than 12 months Fair Value	46	748
Less than 12 months Unrealized Losses	0	74
12 months or longer Fair Value	768	574
12 months or longer Unrealized Losses	114	143
Dollar-denominated | Fixed Maturities | Municipalities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	73	177
Total Unrealized Losses	3	12
Less than 12 months Fair Value	52	145
Less than 12 months Unrealized Losses	2	8
12 months or longer Fair Value	21	32
12 months or longer Unrealized Losses	1	4
Dollar-denominated | Fixed Maturities | Public Utilities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	1,536	2,023
Total Unrealized Losses	60	183
Less than 12 months Fair Value	445	1,740
Less than 12 months Unrealized Losses	7	143
12 months or longer Fair Value	1,091	283
12 months or longer Unrealized Losses	53	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	320	547
Total Unrealized Losses	11	33
Less than 12 months Fair Value	34	454
Less than 12 months Unrealized Losses	1	23
12 months or longer Fair Value	286	93
12 months or longer Unrealized Losses	10	10
Dollar-denominated | Fixed Maturities | Other Corporate
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	10,837	11,588
Total Unrealized Losses	475	1,170
Less than 12 months Fair Value	2,699	8,504
Less than 12 months Unrealized Losses	46	733
12 months or longer Fair Value	8,138	3,084
12 months or longer Unrealized Losses	429	437
Dollar-denominated | Fixed Maturities | US government and agencies
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	167	36
Total Unrealized Losses	2	4
Less than 12 months Fair Value	167	36
Less than 12 months Unrealized Losses	2	4
12 months or longer Fair Value	0	0
12 months or longer Unrealized Losses	0	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