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Business Developments And Risks And Uncertainties (Narrative) (Detail) $ in Millions |  |  |  | 1 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | ---
Jan. 31, 2022 USD ($) | Jan. 01, 2022 USD ($) | Oct. 18, 2021 | Oct. 31, 2021 USD ($) | Feb. 28, 2021 USD ($) | Jan. 31, 2021 USD ($) | Dec. 31, 2021 USD ($) segments
Business Acquisition [Line Items] |  |  |  |  |  |  |
Number of operating segments | segments |  |  |  |  |  |  | 3
Federal legislation passed to combat the economic impact |  |  |  |  |  |  | $ 2,700,000
Percentage of voters voted by the deadline |  |  |  |  |  |  | 27.00%
New Relief Plan Proposed To Stabilize The Finanacial System |  |  |  |  |  |  | $ 1,900,000
Aid Allocated To State And Local Governments |  |  |  |  |  |  | 350,000
Puerto Rico Electric Power Authority [Member] |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |
Bankruptcy claims sold |  |  |  | $ 199 |  |  |
Puerto Rico GO exposure [Member] |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |
Percentage of voters voted by the deadline |  |  | 27.00% |  |  |  |
Credit Suisse [Member] |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |
Damages Paid Value |  |  |  |  | $ 600 |  |
Damages Sought Value |  |  |  |  |  | $ 604 |
Subsequent Event [Member] | Puerto Rico Electric Power Authority [Member] |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |
Bankruptcy claims sold | $ 231 |  |  |  |  |  |
Percentage rate of claim which reduces potential volatility and ongoing risk | 35.00% |  |  |  |  |  |
Gfl Medium Term Notes [Member] |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |
Debt instrument, Repurchase amount |  |  |  |  |  |  | $ 111
Percentage of Weighted Average Cost of Notes Repurchased |  |  |  |  |  |  | 73.00%
Puerto Rico [Member] |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |
Claims payments |  |  |  |  |  |  | $ 277
Outstanding bonds |  |  |  |  |  |  | $ 2,600
Puerto Rico [Member] | Subsequent Event [Member] |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |
Claims payments |  | $ 47 |  |  |  |  |

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