Leases (Narrative) (Detail) - USD ($) $ in Millions |
1 Months Ended | 3 Months Ended | 6 Months Ended | |||
|---|---|---|---|---|---|---|
Apr. 30, 2024 |
Jun. 30, 2025 |
Jun. 30, 2024 |
Mar. 31, 2024 |
Jun. 30, 2025 |
Jun. 30, 2024 |
|
| Leases Disclosure [Line Items] | ||||||
| Payment of settlement of an agreement related to the offshore wind installation vessel under development | $ 47 | |||||
| Charge in connection with settlement of an agreement | $ 47 | |||||
| Charge in connection with settlement of an agreement, after tax | $ 35 | |||||
| Power Purchase Arrangement | ||||||
| Leases Disclosure [Line Items] | ||||||
| Rental revenue | $ 5 | $ 6 | $ 9 | $ 9 | ||
| Operating Lease, Lease Income, Statement of Income or Comprehensive Income [Extensible Enumeration] | Revenues | Revenues | Revenues | Revenues | ||
| Depreciation expense | $ 4 | $ 5 | $ 3 | |||
| Power Purchase Arrangement | Maximum | ||||||
| Leases Disclosure [Line Items] | ||||||
| Depreciation expense | $ 1 | |||||