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