Derivative Instruments And Hedging Activities - Summary of Notional Amounts of Outstanding Foreign Exchange Forwards (Detail) - Not Designated as Accounting Hedges ₽ in Millions, € in Millions, ₨ in Millions, ¥ in Millions, £ in Millions, $ in Millions, $ in Millions, $ in Millions	Sep. 30, 2020 USD ($)	Sep. 30, 2020 EUR (€)	Sep. 30, 2020 GBP (£)	Sep. 30, 2020 JPY (¥)	Sep. 30, 2020 CAD ($)	Sep. 30, 2020 SGD ($)	Sep. 30, 2020 RUB (₽)	Sep. 30, 2020 INR (₨)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 EUR (€)	Dec. 31, 2019 GBP (£)	Dec. 31, 2019 JPY (¥)	Dec. 31, 2019 CAD ($)	Dec. 31, 2019 SGD ($)	Dec. 31, 2019 RUB (₽)	Dec. 31, 2019 INR (₨)
Contracts to sell USD for GBP
Derivative [Line Items]
Notional Amount	$ 320		£ 254						$ 235		£ 178
Contracts to sell USD for Japanese Yen
Derivative [Line Items]
Notional Amount	10			¥ 1,000					29			¥ 3,200
Contracts to sell USD for Canadian dollars
Derivative [Line Items]
Notional Amount	105				$ 140				83				$ 110
Contracts to sell USD for Singapore dollars
Derivative [Line Items]
Notional Amount	58					$ 79			41					$ 56
Contracts to sell USD for Euros
Derivative [Line Items]
Notional Amount	530	€ 452							421	€ 378
Contracts to sell Euros for GBP
Derivative [Line Items]
Notional Amount		€ 53	£ 48							€ 25	£ 21
Contracts to sell USD for Russian Ruble
Derivative [Line Items]
Notional Amount	9						₽ 670		0						₽ 0
Contracts to sell USD for Indian Rupee
Derivative [Line Items]
Notional Amount	$ 18							₨ 1,350	$ 0							₨ 0