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Derivative Instruments (Credit Derivatives Sold) (Detail) - USD ($) $ in Millions | 6 Months Ended | 12 Months Ended
--- | --- | ---
Jun. 30, 2021 | Dec. 31, 2020
Insured Swaps [Member] |  |
Derivative [Line Items] |  |
Weighted average remaining expected maturity | 13 years 6 months | 13 years 10 months 24 days
Insurance Operations [Member] |  |
Derivative [Line Items] |  |
Derivative notional amount | $ 1,719 | $ 1,743
Total fair value of credit derivatives | (1) | (2)
Insurance Operations [Member] | Insured Swaps [Member] |  |
Derivative [Line Items] |  |
Derivative notional amount | 1,719 | 1,743
Total fair value of credit derivatives | (1) | (2)
Credit Rating Aaa [Member] | Insurance Operations [Member] |  |
Derivative [Line Items] |  |
Derivative notional amount | 0 | 0
Total fair value of credit derivatives | 0 | 0
Credit Rating Aaa [Member] | Insurance Operations [Member] | Insured Swaps [Member] |  |
Derivative [Line Items] |  |
Derivative notional amount | 0 | 0
Credit Rating Aa [Member] | Insurance Operations [Member] |  |
Derivative [Line Items] |  |
Derivative notional amount | 55 | 58
Total fair value of credit derivatives | 0 | 0
Credit Rating Aa [Member] | Insurance Operations [Member] | Insured Swaps [Member] |  |
Derivative [Line Items] |  |
Derivative notional amount | 55 | 58
Credit Rating A [Member] | Insurance Operations [Member] |  |
Derivative [Line Items] |  |
Derivative notional amount | 1,306 | 1,327
Total fair value of credit derivatives | (1) | (1)
Credit Rating A [Member] | Insurance Operations [Member] | Insured Swaps [Member] |  |
Derivative [Line Items] |  |
Derivative notional amount | 1,306 | 1,327
Credit Rating Bbb [Member] | Insurance Operations [Member] |  |
Derivative [Line Items] |  |
Derivative notional amount | 358 | 358
Total fair value of credit derivatives | 0 | (1)
Credit Rating Bbb [Member] | Insurance Operations [Member] | Insured Swaps [Member] |  |
Derivative [Line Items] |  |
Derivative notional amount | 358 | 358
Credit Rating Below Investment Grade [Member] | Insurance Operations [Member] |  |
Derivative [Line Items] |  |
Derivative notional amount | 0 | 0
Credit Rating Below Investment Grade [Member] | Insurance Operations [Member] | Insured Swaps [Member] |  |
Derivative [Line Items] |  |
Derivative notional amount | $ 0 | $ 0

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- Definition Fair value of credit risk derivative liability. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4K -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5708775-113959 + Details
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- Definition Nominal or face amount used to calculate payment on derivative. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959 + Details
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