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Employee Benefit Plans (Significant Unobservable Inputs) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2024 | Dec. 31, 2023
Pension Benefits |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | $ 8,270 | $ 8,294
Purchases, sales, issuances and settlements, net | (36) | (35)
Estimated fair value of plan assets at December 31, | 7,836 | 8,270
Pension Benefits | Foreign government |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 810 |
Estimated fair value of plan assets at December 31, | 731 | 810
Pension Benefits | Other (1) |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 699 |
Estimated fair value of plan assets at December 31, | 446 | 699
Pension Benefits | Equity Securities |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 610 |
Estimated fair value of plan assets at December 31, | 695 | 610
Pension Benefits | Other investments |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 869 |
Estimated fair value of plan assets at December 31, | 727 | 869
Pension Benefits | Corporate fixed maturity securities |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 3,083 |
Estimated fair value of plan assets at December 31, | 3,081 | 3,083
Other Postretirement Benefits |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 1,334 | 1,303
Purchases, sales, issuances and settlements, net | (2) | 0
Estimated fair value of plan assets at December 31, | 1,329 | 1,334
Other Postretirement Benefits | Foreign government |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 46 |
Estimated fair value of plan assets at December 31, | 38 | 46
Other Postretirement Benefits | Other (1) |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 37 |
Estimated fair value of plan assets at December 31, | 66 | 37
Other Postretirement Benefits | Equity Securities |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 59 |
Estimated fair value of plan assets at December 31, | 58 | 59
Other Postretirement Benefits | Other investments |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 1 |
Estimated fair value of plan assets at December 31, | 1 | 1
Other Postretirement Benefits | Corporate fixed maturity securities |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 167 |
Estimated fair value of plan assets at December 31, | 175 | 167
Level 3 | Pension Benefits |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 904 |
Estimated fair value of plan assets at December 31, | 748 | 904
Level 3 | Pension Benefits | Foreign government |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 2 | 0
Realized gains (losses) | 0 | 0
Unrealized gains (losses) | 0 | 0
Purchases, sales, issuances and settlements, net | 0 | 0
Transfers into and/or out of Level 3 | 0 | 2
Estimated fair value of plan assets at December 31, | 2 | 2
Level 3 | Pension Benefits | Other (1) |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 8 | 3
Realized gains (losses) | 0 | 0
Unrealized gains (losses) | (1) | 0
Purchases, sales, issuances and settlements, net | (4) | 0
Transfers into and/or out of Level 3 | (1) | 5
Estimated fair value of plan assets at December 31, | 2 | 8
Level 3 | Pension Benefits | Equity Securities |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 12 | 3
Realized gains (losses) | 0 | 0
Unrealized gains (losses) | 0 | 1
Purchases, sales, issuances and settlements, net | (4) | 8
Transfers into and/or out of Level 3 | 0 | 0
Estimated fair value of plan assets at December 31, | 8 | 12
Level 3 | Pension Benefits | Other investments |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 828 | 855
Realized gains (losses) | 0 | (1)
Unrealized gains (losses) | (24) | (51)
Purchases, sales, issuances and settlements, net | (124) | 25
Transfers into and/or out of Level 3 | 0 | 0
Estimated fair value of plan assets at December 31, | 680 | 828
Level 3 | Pension Benefits | Corporate fixed maturity securities |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 54 | 55
Realized gains (losses) | 0 | 0
Unrealized gains (losses) | (2) | 1
Purchases, sales, issuances and settlements, net | 16 | 2
Transfers into and/or out of Level 3 | (12) | (4)
Estimated fair value of plan assets at December 31, | 56 | 54
Level 3 | Pension Benefits | Derivative Financial Instruments, Assets |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 0 | 4
Realized gains (losses) | 0 | 0
Unrealized gains (losses) | 0 | (1)
Purchases, sales, issuances and settlements, net | 0 | (3)
Transfers into and/or out of Level 3 | 0 | 0
Estimated fair value of plan assets at December 31, | 0 | 0
Level 3 | Other Postretirement Benefits |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 0 |
Estimated fair value of plan assets at December 31, | 0 | 0
Level 3 | Other Postretirement Benefits | Foreign government |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 0 |
Estimated fair value of plan assets at December 31, | 0 | 0
Level 3 | Other Postretirement Benefits | Other (1) |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 0 |
Estimated fair value of plan assets at December 31, | 0 | 0
Level 3 | Other Postretirement Benefits | Equity Securities |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 0 |
Estimated fair value of plan assets at December 31, | 0 | 0
Level 3 | Other Postretirement Benefits | Other investments |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 0 |
Estimated fair value of plan assets at December 31, | 0 | 0
Level 3 | Other Postretirement Benefits | Corporate fixed maturity securities |  |
Rollforward fair value measurement using significant unobservable inputs (level 3) [Roll Forward] |  |
Estimated fair value of plan assets at January 1, | 0 |
Estimated fair value of plan assets at December 31, | $ 0 | $ 0

X
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- Definition Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan from actual return (loss) on assets still held. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 17 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480482/715-20-55-17 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(02)(A) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
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- Definition Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 17 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480482/715-20-55-17 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(02) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(ii) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(01) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 Reference 6: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(ii) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 Reference 7: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(01) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
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- Definition Amount, measured using unobservable input, of increase (decrease) in plan asset of defined benefit plan from purchase, sale and settlement of trade associated with underlying investment. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 17 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480482/715-20-55-17 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(02)(B) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
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- Definition Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan, for assets transferred into (out of) Level 3 of fair value hierarchy. Includes, but is not limited to, transfer due to change in observability of significant inputs. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 17 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480482/715-20-55-17 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(02)(C) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
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