Derivatives and Hedging - Additional Information (Detail) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
|
| Derivative [Line Items] | ||
| Derivative maximum risk of loss | $ 17 | $ 17 |
| Forward Foreign Currency Exchange Contracts [Member] | ||
| Derivative [Line Items] | ||
| Notional value | $ 2,800 | $ 3,400 |
| Derivative Expiration Dates | 2021-01 | 2020-01 |
| Total Return Swaps [Member] | ||
| Derivative [Line Items] | ||
| Notional value | $ 833 | $ 644 |