v3.26.3
Investments (Securities Pledged as Collateral Related to Repurchase Reverse Repurchase Program) (Details) - USD ($)
$ in Millions
Sep. 30, 2026
Dec. 31, 2025
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral $ 702 $ 831
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 2,319 2,623
Obligation to Return Securities Received as Collateral 3,021 3,454
Corporate Debt Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 355 428
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 1,281 1,336
Debt Security, Government, Non-US [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 14 21
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 65 107
Canadian and Canadian provincial governments    
Assets Sold under Agreements to Repurchase [Line Items]    
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 12 12
Asset-backed Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 8 25
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 73 148
Commercial Mortgage Backed Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 29 37
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 214 276
Residential mortgage-backed securities    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 8 10
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 38 89
JAPAN    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 288 310
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 377 378
US Government Agencies Debt Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 259 277
Maturity Overnight [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 0 0
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 0
Obligation to Return Securities Received as Collateral 0 0
Maturity Overnight [Member] | Corporate Debt Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 0 0
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 0
Maturity Overnight [Member] | Debt Security, Government, Non-US [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 0 0
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 0
Maturity Overnight [Member] | Canadian and Canadian provincial governments    
Assets Sold under Agreements to Repurchase [Line Items]    
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 0
Maturity Overnight [Member] | Asset-backed Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 0 0
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 0
Maturity Overnight [Member] | Commercial Mortgage Backed Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 0 0
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 0
Maturity Overnight [Member] | Residential mortgage-backed securities    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 0 0
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 0
Maturity Overnight [Member] | JAPAN    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 0 0
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 0
Maturity Overnight [Member] | US Government Agencies Debt Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 0
Maturity up to 30 days [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 82 0
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 0
Obligation to Return Securities Received as Collateral 82 0
Maturity up to 30 days [Member] | Corporate Debt Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 0 0
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 0
Maturity up to 30 days [Member] | Debt Security, Government, Non-US [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 0 0
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 0
Maturity up to 30 days [Member] | Canadian and Canadian provincial governments    
Assets Sold under Agreements to Repurchase [Line Items]    
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 0
Maturity up to 30 days [Member] | Asset-backed Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 0 0
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 0
Maturity up to 30 days [Member] | Commercial Mortgage Backed Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 0 0
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 0
Maturity up to 30 days [Member] | Residential mortgage-backed securities    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 0 0
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 0
Maturity up to 30 days [Member] | JAPAN    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 82 0
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 0
Maturity up to 30 days [Member] | US Government Agencies Debt Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 0
Maturity 30 to 90 Days [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 280 444
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 366 309
Obligation to Return Securities Received as Collateral 646 753
Maturity 30 to 90 Days [Member] | Corporate Debt Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 227 357
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 340 0
Maturity 30 to 90 Days [Member] | Debt Security, Government, Non-US [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 10 15
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 26 0
Maturity 30 to 90 Days [Member] | Canadian and Canadian provincial governments    
Assets Sold under Agreements to Repurchase [Line Items]    
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 0
Maturity 30 to 90 Days [Member] | Asset-backed Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 6 25
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 11
Maturity 30 to 90 Days [Member] | Commercial Mortgage Backed Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 29 37
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 49
Maturity 30 to 90 Days [Member] | Residential mortgage-backed securities    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 8 10
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 42
Maturity 30 to 90 Days [Member] | JAPAN    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 0 0
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 203
Maturity 30 to 90 Days [Member] | US Government Agencies Debt Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 0 4
Maturity over 90 days [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 340 387
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 1,953 2,314
Obligation to Return Securities Received as Collateral 2,293 2,701
Maturity over 90 days [Member] | Corporate Debt Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 128 71
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 941 1,336
Maturity over 90 days [Member] | Debt Security, Government, Non-US [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 4 6
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 39 107
Maturity over 90 days [Member] | Canadian and Canadian provincial governments    
Assets Sold under Agreements to Repurchase [Line Items]    
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 12 12
Maturity over 90 days [Member] | Asset-backed Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 2 0
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 73 137
Maturity over 90 days [Member] | Commercial Mortgage Backed Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 0 0
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 214 227
Maturity over 90 days [Member] | Residential mortgage-backed securities    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 0 0
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 38 47
Maturity over 90 days [Member] | JAPAN    
Assets Sold under Agreements to Repurchase [Line Items]    
Securities Loaned, Fair Value of Collateral 206 310
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement 377 175
Maturity over 90 days [Member] | US Government Agencies Debt Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
FinancialAssetsSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement $ 259 $ 273