Derivative Instruments And Hedging Activities - Summary of Notional Amounts of Outstanding Forward Contracts Designated as a Net Investment Hedge (Detail) - Dec. 31, 2020 - Net Investment Hedging - Designated as Hedging Instrument € in Millions, £ in Millions, $ in Millions	USD ($)	EUR (€)	GBP (£)
Contract to sell EUR for USD
Derivative [Line Items]
Notional Amount	$ 627	€ 524
Contract to sell GBP for EUR
Derivative [Line Items]
Notional Amount		€ 148	£ 134