Financial Instruments - Cross Currency Risk Exposures Interest Rate Swaps (Detail) - USD ($) $ in Millions |
Dec. 31, 2021 |
Dec. 31, 2020 |
|---|---|---|
| Disclosure of detailed information about hedges [Line Items] | ||
| Borrowings after currency hedging arrangements | $ 3,687 | $ 3,672 |
| Borrowings before currency hedging arrangements | 3,786 | 3,772 |
| Canada, Dollars [member] | ||
| Disclosure of detailed information about hedges [Line Items] | ||
| Borrowings after currency hedging arrangements | 0 | |
| Borrowings before currency hedging arrangements | 1,103 | 1,093 |
| United States of America, Dollars [member] | ||
| Disclosure of detailed information about hedges [Line Items] | ||
| Borrowings after currency hedging arrangements | 3,687 | 3,672 |
| Borrowings before currency hedging arrangements | $ 2,683 | $ 2,679 |