DERIVATIVE INSTRUMENTS - Maximum Potential Risk, Fair Value, Weighted-Average Years to Maturity, and Underlying Referenced Credit Obligation Type for Credit Default Swaps (Detail) (Corporate Bonds, USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Credit Derivatives [Line Items]
Maximum potential risk	$ (327)	$ (355)
Estimated fair value	(44)	(65)
Less than one year
Credit Derivatives [Line Items]
Maximum potential risk	0	0
Estimated fair value	0	0
One to three years
Credit Derivatives [Line Items]
Maximum potential risk	(119)	(133)
Estimated fair value	2	2
Three to five years
Credit Derivatives [Line Items]
Maximum potential risk	(107)	(106)
Estimated fair value	(32)	(47)
Five to ten years
Credit Derivatives [Line Items]
Maximum potential risk	(101)	(116)
Estimated fair value	(14)	(20)
A
Credit Derivatives [Line Items]
Credit Rating	A	A
Maximum potential risk	(119)	(133)
Estimated fair value	2	2
A | Less than one year
Credit Derivatives [Line Items]
Maximum potential risk	0	0
Estimated fair value	0	0
A | One to three years
Credit Derivatives [Line Items]
Maximum potential risk	(119)	(133)
Estimated fair value	2	2
A | Three to five years
Credit Derivatives [Line Items]
Maximum potential risk	0	0
Estimated fair value	0	0
A | Five to ten years
Credit Derivatives [Line Items]
Maximum potential risk	0	0
Estimated fair value	0	0
BB or Lower
Credit Derivatives [Line Items]
Credit Rating	BB or lower	BB or lower
Maximum potential risk	(208)	(222)
Estimated fair value	(46)	(67)
BB or Lower | Less than one year
Credit Derivatives [Line Items]
Maximum potential risk	0	0
Estimated fair value	0	0
BB or Lower | One to three years
Credit Derivatives [Line Items]
Maximum potential risk	0	0
Estimated fair value	0	0
BB or Lower | Three to five years
Credit Derivatives [Line Items]
Maximum potential risk	(107)	(106)
Estimated fair value	(32)	(47)
BB or Lower | Five to ten years
Credit Derivatives [Line Items]
Maximum potential risk	(101)	(116)
Estimated fair value	$ (14)	$ (20)