INVESTMENTS - Details of Holdings of Perpetual Securities (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Investment Holdings [Line Items]
Amortized Cost	$ 57,646	$ 52,275
Fair Value	61,578	54,036
Perpetual securities
Investment Holdings [Line Items]
Amortized Cost	4,213	6,897
Fair Value	4,302	6,439
Unrealized Gain (Loss)	89	(458)
Perpetual securities \| Upper Tier II
Investment Holdings [Line Items]
Amortized Cost	2,825	4,285
Fair Value	2,919	4,244
Unrealized Gain (Loss)	94	(41)
Perpetual securities \| Upper Tier II \| AA
Investment Holdings [Line Items]
Amortized Cost	0	196
Fair Value	0	204
Unrealized Gain (Loss)	0	8
Perpetual securities \| Upper Tier II \| A
Investment Holdings [Line Items]
Amortized Cost	460	2,108
Fair Value	488	2,046
Unrealized Gain (Loss)	28	(62)
Perpetual securities \| Upper Tier II \| BBB
Investment Holdings [Line Items]
Amortized Cost	2,077	1,791
Fair Value	2,129	1,804
Unrealized Gain (Loss)	52	13
Perpetual securities \| Upper Tier II \| BB or Lower
Investment Holdings [Line Items]
Amortized Cost	288	190
Fair Value	302	190
Unrealized Gain (Loss)	14	0
Perpetual securities \| Tier I
Investment Holdings [Line Items]
Amortized Cost	1,079	2,268
Fair Value	1,031	1,834
Unrealized Gain (Loss)	(48)	(434)
Perpetual securities \| Tier I \| A
Investment Holdings [Line Items]
Amortized Cost	0	0
Fair Value	0	0
Unrealized Gain (Loss)	0	0
Perpetual securities \| Tier I \| BBB
Investment Holdings [Line Items]
Amortized Cost	966	1,684
Fair Value	904	1,417
Unrealized Gain (Loss)	(62)	(267)
Perpetual securities \| Tier I \| BB or Lower
Investment Holdings [Line Items]
Amortized Cost	113	584
Fair Value	127	417
Unrealized Gain (Loss)	14	(167)
Perpetual securities \| Other subordinated - non-banks \| BBB
Investment Holdings [Line Items]
Amortized Cost	309	344
Fair Value	352	361
Unrealized Gain (Loss)	$ 43	$ 17

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 12

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

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-Section 45

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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Reference 5: http://www.xbrl.org/2003/role/presentationRef

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-Number FAS115-1/124-1

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

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Reference 9: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

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Reference 10: http://www.xbrl.org/2003/role/presentationRef

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-Name Statement of Financial Accounting Standard (FAS)

-Number 133

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+ Details

- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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