Components of the Gain or Loss on Derivatives that Qualified as Cash Flow Hedges (Detail) (Cash flow hedges, USD $) In Millions	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income on Derivative (Effective Portion)	$ 0	$ 2	$ (38)	$ 0
Net Realized Investment Gains (Losses) Recognized in Income on Derivative (Ineffective Portion)	0	13	(2)	13
Interest rate swaps
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income on Derivative (Effective Portion)	1	0	2	1
Net Realized Investment Gains (Losses) Recognized in Income on Derivative (Ineffective Portion)	0	0	0	0
Foreign currency swaps
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income on Derivative (Effective Portion)	(1)	2	(40)	(1)
Net Realized Investment Gains (Losses) Recognized in Income on Derivative (Ineffective Portion)	$ 0	$ 13	$ (2)	$ 13

The portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments representing (a) the amount of the hedge ineffectiveness and (b) the amount, if any, excluded from the assessment of hedge effectiveness.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 205G

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4C

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5624171-113959

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 25

-Section 50

-Paragraph 1

-Subparagraph (a)(1),(2)

-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 44C

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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