INVESTMENTS - Pretax Other-Than-Temporary Impairment Losses by Investment Category (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment losses	$ 97	[1]	$ 166	[2]	$ 643	[1]	$ 1,100	[2]
Change in intent impairment
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment losses	0				251
Credit-related impairment
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment losses	70				365
Severity and duration of decline in fair value impairment
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment losses	27				27
Perpetual Securities
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment losses	27		122		243		306
Corporate Bonds
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment losses	70		43		253		783
Mortgage- and asset-backed Securities
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment losses	0		1		3		9
Municipalities
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment losses	0		0		0		1
Sovereign and Supranational
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment losses	0		0		144		0
Equity Securities
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment losses	$ 0		$ 0		$ 0		$ 1

[1] Includes $70 and $365 for the three- and nine-month periods ended September 30, 2012, respectively, for credit-related impairments; $0 and $251 for the three- and nine-month periods ended September 30, 2012, respectively, from change in intent to sell securities; and $27 for the three- and nine-month periods ended September 30, 2012 for impairments due to severity and duration of decline in fair value

[2] Consisted completely of credit-related impairments