Postretirement Benefit Obligations - Schedule of Net Benefit Costs (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
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| Postemployment Benefits [Abstract] | ||||
| Postretirement benefits service cost | $ 0 | $ 0 | $ 1 | $ 1 |
| Postretirement benefit (gain) loss | ||||
| Interest cost | 17 | 17 | 33 | 34 |
| Expected return on plan assets | (18) | (18) | (37) | (37) |
| Amortization of: | ||||
| Postretirement prior service cost (credit) | (1) | (1) | (2) | (2) |
| Postretirement benefit (gain) loss, net | (2) | (2) | (6) | (5) |
| Net periodic defined benefit cost (credit) | $ (2) | $ (2) | $ (5) | $ (4) |
| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Amount of prior service cost (credit) recognized in net periodic benefit cost (credit) of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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| X | ||||||||||
- Definition Amount of expected return (loss) recognized in net periodic benefit (cost) credit, calculated based on expected long-term rate of return and market-related value of plan assets of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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| X | ||||||||||
- Definition Amount of cost recognized for passage of time related to defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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| X | ||||||||||
- Definition Amount of net periodic benefit cost (credit) for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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| X | ||||||||||
- Definition Amount of expense (reversal of expense) for net periodic benefit cost components, excluding service cost component, of defined benefit plan. Amount includes, but is not limited to, interest cost, expected (return) loss on plan asset, amortization of prior service cost (credit), amortization of (gain) loss, amortization of transition (asset) obligation, settlement (gain) loss, curtailment (gain) loss and certain termination benefits. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- References No definition available.
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