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Employee Benefits - Amounts Recognized in Accumulated Other Comprehensive Loss That Have Not Yet Been Recognized (Details) - Pension Plan - USD ($) $ in Millions | Dec. 31, 2024 | Dec. 31, 2023
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U.K. |  |
Amounts recognized in Accumulated other comprehensive loss unrecognized as components of net periodic benefit cost |  |
Net loss | $ 1,854 | $ 1,870
Prior service cost (income) | 43 | 39
Net amount recognized | 1,897 | 1,909
Other |  |
Amounts recognized in Accumulated other comprehensive loss unrecognized as components of net periodic benefit cost |  |
Net loss | 419 | 436
Prior service cost (income) | (5) | (5)
Net amount recognized | 414 | 431
U.S. |  |
Amounts recognized in Accumulated other comprehensive loss unrecognized as components of net periodic benefit cost |  |
Net loss | 1,276 | 1,319
Prior service cost (income) | 0 | 0
Net amount recognized | $ 1,276 | $ 1,319

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