INVESTMENTS - Fair Value and Gross Unrealized Losses for Securities That Have Been in Continuous Unrealized Loss Position (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	$ 36,214	$ 40,697
Total Unrealized Losses	2,746	1,582
Less Than 12 months Fair Value	27,790	28,258
Less Than 12 months Unrealized Losses	1,376	368
12 months or longer Fair Value	8,424	12,439
12 months or longer Unrealized Losses	1,370	1,214
Fixed Maturities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	34,828	39,240
Total Unrealized Losses	2,519	1,411
Less Than 12 months Fair Value	26,985	28,135
Less Than 12 months Unrealized Losses	1,293	368
12 months or longer Fair Value	7,843	11,105
12 months or longer Unrealized Losses	1,226	1,043
Fixed Maturities | Japan government and agencies | Yen Denominated
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	8,869	17,342
Total Unrealized Losses	34	148
Less Than 12 months Fair Value	8,869	17,342
Less Than 12 months Unrealized Losses	34	148
12 months or longer Fair Value	0	0
12 months or longer Unrealized Losses	0	0
Fixed Maturities | Municipalities | Dollar Denominated
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	177	34
Total Unrealized Losses	12	6
Less Than 12 months Fair Value	145	1
Less Than 12 months Unrealized Losses	8	0
12 months or longer Fair Value	32	33
12 months or longer Unrealized Losses	4	6
Fixed Maturities | Municipalities | Yen Denominated
Investments, Unrealized Loss Position [Line Items]
Total Fair Value		56
Total Unrealized Losses		2
Less Than 12 months Fair Value		56
Less Than 12 months Unrealized Losses		2
12 months or longer Fair Value		0
12 months or longer Unrealized Losses		0
Fixed Maturities | Mortgage- and asset-backed Securities | Yen Denominated
Investments, Unrealized Loss Position [Line Items]
Total Fair Value		136
Total Unrealized Losses		1
Less Than 12 months Fair Value		0
Less Than 12 months Unrealized Losses		0
12 months or longer Fair Value		136
12 months or longer Unrealized Losses		1
Fixed Maturities | Public Utilities | Dollar Denominated
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	2,023	736
Total Unrealized Losses	183	17
Less Than 12 months Fair Value	1,740	736
Less Than 12 months Unrealized Losses	143	17
12 months or longer Fair Value	283	0
12 months or longer Unrealized Losses	40	0
Fixed Maturities | Public Utilities | Yen Denominated
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	2,519	3,920
Total Unrealized Losses	140	178
Less Than 12 months Fair Value	1,816	1,339
Less Than 12 months Unrealized Losses	54	31
12 months or longer Fair Value	703	2,581
12 months or longer Unrealized Losses	86	147
Fixed Maturities | Sovereign and Supranational | Dollar Denominated
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	12	31
Total Unrealized Losses	1	2
Less Than 12 months Fair Value	12	0
Less Than 12 months Unrealized Losses	1	0
12 months or longer Fair Value	0	31
12 months or longer Unrealized Losses	0	2
Fixed Maturities | Sovereign and Supranational | Yen Denominated
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	1,152	1,244
Total Unrealized Losses	100	84
Less Than 12 months Fair Value	791	507
Less Than 12 months Unrealized Losses	34	13
12 months or longer Fair Value	361	737
12 months or longer Unrealized Losses	66	71
Fixed Maturities | Banks/financial Institutions | Dollar Denominated
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	547	276
Total Unrealized Losses	33	6
Less Than 12 months Fair Value	454	180
Less Than 12 months Unrealized Losses	23	3
12 months or longer Fair Value	93	96
12 months or longer Unrealized Losses	10	3
Fixed Maturities | Banks/financial Institutions | Yen Denominated
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	4,533	6,918
Total Unrealized Losses	570	611
Less Than 12 months Fair Value	2,322	1,935
Less Than 12 months Unrealized Losses	107	28
12 months or longer Fair Value	2,211	4,983
12 months or longer Unrealized Losses	463	583
Fixed Maturities | Other Corporate | Dollar Denominated
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	11,588	4,534
Total Unrealized Losses	1,170	95
Less Than 12 months Fair Value	8,504	4,404
Less Than 12 months Unrealized Losses	733	86
12 months or longer Fair Value	3,084	130
12 months or longer Unrealized Losses	437	9
Fixed Maturities | Other Corporate | Yen Denominated
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	3,372	4,013
Total Unrealized Losses	272	261
Less Than 12 months Fair Value	2,296	1,635
Less Than 12 months Unrealized Losses	152	40
12 months or longer Fair Value	1,076	2,378
12 months or longer Unrealized Losses	120	221
Fixed Maturities | US government and agencies | Dollar Denominated
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
Perpetual securities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	1,381	1,451
Total Unrealized Losses	226	170
Less Than 12 months Fair Value	800	120
Less Than 12 months Unrealized Losses	82	0
12 months or longer Fair Value	581	1,331
12 months or longer Unrealized Losses	144	170
Perpetual securities | Dollar Denominated
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	59	136
Total Unrealized Losses	9	9
Less Than 12 months Fair Value	52	120
Less Than 12 months Unrealized Losses	8	0
12 months or longer Fair Value	7	16
12 months or longer Unrealized Losses	1	9
Perpetual securities | Yen Denominated
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	1,322	1,315
Total Unrealized Losses	217	161
Less Than 12 months Fair Value	748	0
Less Than 12 months Unrealized Losses	74	0
12 months or longer Fair Value	574	1,315
12 months or longer Unrealized Losses	143	161
Equity securities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	5	6
Total Unrealized Losses	1	1
Less Than 12 months Fair Value	5	3
Less Than 12 months Unrealized Losses	1	0
12 months or longer Fair Value	0	3
12 months or longer Unrealized Losses	$ 0	$ 1