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Income Taxes (Narrative) (Detail) (USD $) | 3 Months Ended | 6 Months Ended | 12 Months Ended
--- | --- | --- | ---
Jun. 30, 2012 | Jun. 30, 2012 | Jun. 30, 2011 | Dec. 31, 2011
Non-Variable Interest Entities [Line Items] |  |  |  |
Federal statutory rate | 35.00% | 35.00% | 35.00% | 35.00%
Net deferred tax asset | $ 1,400,000,000 | $ 1,400,000,000 |  |
Capital losses carryforward period in years | 5 years |  |  |
Taxable income projections, years |  | 15 years |  |
Maximum taxable income projections, years |  | 20 years |  |
Deferred tax assets related to net unrealized losses on investments | 18,000,000 | 18,000,000 |  |
Total deferred tax assets |  | 1,400,000,000 |  |
Capital loss carryforward |  |  |  | 155,000,000
NOL carryforward |  |  |  | 943,000,000
Minimum tax credit carryforward |  |  |  | 22,000,000
Non Variable Interest Entities [Member] |  |  |  |
Non-Variable Interest Entities [Line Items] |  |  |  |
Net deferred tax asset | 1,396,000,000 | 1,396,000,000 |  | 1,745,000,000
Valuation allowance | 194,000,000 | 194,000,000 |  | 236,000,000
Valuation allowance increase | $ 42,000,000 |  |  |

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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible capital loss carryforwards. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32632-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32621-109319 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 25 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=6969291&loc=d3e28680-109314 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 43 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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. + Details
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