INVESTMENTS - Details of Holdings of Perpetual Securities (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Investment Holdings [Line Items]
Amortized Cost	$ 60,844	$ 59,515
Fair Value	68,270us-gaap_AvailableForSaleSecurities	61,038us-gaap_AvailableForSaleSecurities
Unrealized Gain (Loss)	7,426	1,523
Perpetual securities
Investment Holdings [Line Items]
Amortized Cost	2,440	2,987
Fair Value	2,669	2,947
Unrealized Gain (Loss)	229	(40)
Upper Tier II \| Perpetual securities
Investment Holdings [Line Items]
Amortized Cost	1,554	1,920
Fair Value	1,645	1,913
Unrealized Gain (Loss)	91	(7)
Upper Tier II \| A \| Perpetual securities
Investment Holdings [Line Items]
Amortized Cost	61	145
Fair Value	87	183
Unrealized Gain (Loss)	26	38
Upper Tier II \| BBB \| Perpetual securities
Investment Holdings [Line Items]
Amortized Cost	1,330	1,563
Fair Value	1,333	1,532
Unrealized Gain (Loss)	3	(31)
Upper Tier II \| BB or Lower \| Perpetual securities
Investment Holdings [Line Items]
Amortized Cost	163	212
Fair Value	225	198
Unrealized Gain (Loss)	62	(14)
Tier I \| Perpetual securities
Investment Holdings [Line Items]
Amortized Cost	703	858
Fair Value	793	825
Unrealized Gain (Loss)	90	(33)
Tier I \| BBB \| Perpetual securities
Investment Holdings [Line Items]
Amortized Cost	519	746
Fair Value	556	706
Unrealized Gain (Loss)	37	(40)
Tier I \| BB or Lower \| Perpetual securities
Investment Holdings [Line Items]
Amortized Cost	184	112
Fair Value	237	119
Unrealized Gain (Loss)	53	7
Other subordinated - non-banks \| BB or Lower \| Perpetual securities
Investment Holdings [Line Items]
Amortized Cost	183	209
Fair Value	231	209
Unrealized Gain (Loss)	$ 48	$ 0

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 Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 5

-Subparagraph (aa)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562

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- 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.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.2)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Amount of unrealized gain (loss) on investments in debt and equity securities classified as available-for-sale securities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 9

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563

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