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Variable Interest Entities (Narrative) (Detail) $ in Millions |  | 3 Months Ended | 12 Months Ended
--- | --- | --- | ---
Jan. 27, 2020 USD ($) | Mar. 31, 2019 USD ($) | Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($)
Variable Interest Entity [Line Items] |  |  |  |
Carrying amounts of assets |  |  | $ 7,284 | $ 8,107
Carrying amounts of liabilities |  |  | 6,445 | 6,975
Additional Voluntary Payment |  |  | 66 |
Variable Interest Entity Primary Beneficiary [Member] |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |
Carrying amounts of assets |  |  | 1,600 | 1,700
Carrying amounts of liabilities |  |  | $ 1,500 | $ 1,700
Variable Interest Entity Primary Beneficiary [Member] | Subsequent Event [Member] |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |
Reduction In Variable Interest Entity Asset And Liabilities | $ 315 |  |  |
Variable Interest Entity Primary Beneficiary [Member] | U S Public Finance Insurance [Member] |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |
Number of variable interest entities consolidated |  | 7 |  |
Net realized gains (losses) related to the initial consolidation |  | $ (42) |  |
Variable Interest Entity Primary Beneficiary [Member] | Structured Finance And International Insurance [Member] |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |
Number of variable interest entities deconsolidated |  |  | 2 | 8
Deconsolidation, Gain (Loss), Amount |  |  | $ (16) | $ (78)
Variable Interest Entity Primary Beneficiary [Member] | Structured Finance And International Insurance [Member] | Subsequent Event [Member] |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |
Number of variable interest entities deconsolidated | 1 |  |  |
Variable Interest Entity Primary Beneficiary [Member] | Structured Finance And International Insurance [Member] | Zohar Funds Bankruptcy Cases Debtors [Member] |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |
Number of variable interest entities deconsolidated |  |  |  | 2
Deconsolidation, Gain (Loss), Amount |  |  |  | $ (93)

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- Definition Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(11)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -URI http://asc.fasb.org/extlink&oid=115929826&loc=d3e8736-108599 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(12)) -URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910 + Details
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- Definition The amount of financial or other support the reporting entity has provided (explicitly or implicitly) to the Variable Interest Entity (VIE) that it was not previously contractually required to provide or that the reporting entity intends to provide, including, for example, situations in which the reporting entity assisted the VIE in obtaining another type of support. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 5A -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=118582676&loc=SL6759159-111685 + Details
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