INVESTMENTS - Details of Holdings of Perpetual Securities (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Investment Holdings [Line Items]
Amortized Cost	$ 56,430	$ 57,646
Fair Value	59,433	61,578
Perpetual Securities
Investment Holdings [Line Items]
Amortized Cost	3,633	4,213
Fair Value	3,133	4,302
Unrealized Gain (Loss)	(500)	89
Perpetual Securities \| Upper Tier II
Investment Holdings [Line Items]
Amortized Cost	2,340	2,825
Fair Value	2,059	2,919
Unrealized Gain (Loss)	(281)	94
Perpetual Securities \| Upper Tier II \| A
Investment Holdings [Line Items]
Amortized Cost	164	460
Fair Value	181	488
Unrealized Gain (Loss)	17	28
Perpetual Securities \| Upper Tier II \| BBB
Investment Holdings [Line Items]
Amortized Cost	1,911	2,077
Fair Value	1,684	2,129
Unrealized Gain (Loss)	(227)	52
Perpetual Securities \| Upper Tier II \| BB or Lower
Investment Holdings [Line Items]
Amortized Cost	265	288
Fair Value	194	302
Unrealized Gain (Loss)	(71)	14
Perpetual Securities \| Tier I
Investment Holdings [Line Items]
Amortized Cost	1,008	1,079
Fair Value	856	1,031
Unrealized Gain (Loss)	(152)	(48)
Perpetual Securities \| Tier I \| BBB
Investment Holdings [Line Items]
Amortized Cost	835	966
Fair Value	669	904
Unrealized Gain (Loss)	(166)	(62)
Perpetual Securities \| Tier I \| BB or Lower
Investment Holdings [Line Items]
Amortized Cost	173	113
Fair Value	187	127
Unrealized Gain (Loss)	14	14
Perpetual Securities \| Other subordinated - non-banks \| BBB
Investment Holdings [Line Items]
Amortized Cost	285	309
Fair Value	218	352
Unrealized Gain (Loss)	$ (67)	$ 43

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

-Name FASB Staff Position (FSP)

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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

-Subparagraph b

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

-Publisher FASB

-Name Accounting Standards Codification

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

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

-Publisher FASB

-Name FASB Staff Position (FSP)

-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

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Reference 7: http://www.xbrl.org/2003/role/presentationRef

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Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 13

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 14

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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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