Business Developments And Risks And Uncertainties (Narrative) (Detail) $ in Millions				6 Months Ended
	Jul. 01, 2022 USD ($)	Mar. 15, 2022 USD ($)	Jan. 01, 2022 USD ($)	Jun. 30, 2022 USD ($) segments	Jul. 08, 2022 USD ($)
Business Acquisition [Line Items]
Number of operating segments | segments				3
GO PSA [Member]
Business Acquisition [Line Items]
Proceeds from GO PSA		$ 1,000
Puerto Rico Electric Power Authority [Member]
Business Acquisition [Line Items]
Percentage rate of claim which reduces potential volatility and ongoing risk				35.00%
National Public Finance Guarantee Corporation [Member] | GO PSA [Member]
Business Acquisition [Line Items]
Conditional value instrument additional recoveries from the percentage of sales and usage tax receipts				5.50%
Acceleration and commutation payment				$ 277
Subsequent Event [Member] | National Public Finance Guarantee Corporation [Member] | Puerto Rico Highway and Transportation Authority [Member]
Business Acquisition [Line Items]
Cash					$ 33
Contingent value instrument					$ 358,000
Maximum [Member] | National Public Finance Guarantee Corporation [Member] | GO and PBA [Member]
Business Acquisition [Line Items]
Outstanding bonds				0
Gross par outstanding				0
Minimum [Member] | National Public Finance Guarantee Corporation [Member] | GO and PBA [Member]
Business Acquisition [Line Items]
Outstanding bonds				495
Gross par outstanding				380
Puerto Rico [Member]
Business Acquisition [Line Items]
Claims payments			$ 47
Outstanding bonds	$ 2,100			$ 2,100
Puerto Rico [Member] | Subsequent Event [Member] | National Public Finance Guarantee Corporation [Member]
Business Acquisition [Line Items]
Claims payments	$ 142