v3.26.1
Derivative Instruments - Gains (Losses) on Derivatives Not Designated as Hedging (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Derivative [Line Items]        
Total gains (losses) for derivatives not designated as hedges $ 617 $ (1,464) $ 1,153 $ (1,802)
Income Statement Location [Axis]: us-gaap:GainLossOnInvestments        
Derivative [Line Items]        
Total gains (losses) for derivatives not designated as hedges 2,752 (577) 1,757 (1,918)
Income Statement Location [Axis]: us-gaap:GainLossOnInvestments | Equity options        
Derivative [Line Items]        
Total gains (losses) for derivatives not designated as hedges 2,847 871 1,692 (65)
Income Statement Location [Axis]: us-gaap:GainLossOnInvestments | Futures        
Derivative [Line Items]        
Total gains (losses) for derivatives not designated as hedges 113 (9) 66 (16)
Income Statement Location [Axis]: us-gaap:GainLossOnInvestments | Swap [Member]        
Derivative [Line Items]        
Total gains (losses) for derivatives not designated as hedges (35) (70) (149) (137)
Income Statement Location [Axis]: us-gaap:GainLossOnInvestments | Foreign currency swaps        
Derivative [Line Items]        
Total gains (losses) for derivatives not designated as hedges 117 (1,009) 553 (1,288)
Income Statement Location [Axis]: us-gaap:GainLossOnInvestments | Foreign currency forwards        
Derivative [Line Items]        
Total gains (losses) for derivatives not designated as hedges (258) (401) (212) (611)
Income Statement Location [Axis]: us-gaap:GainLossOnInvestments | Embedded derivatives        
Derivative [Line Items]        
Total gains (losses) for derivatives not designated as hedges (32) 41 (193) 199
Income Statement Location [Axis]: ahl:InterestSensitiveContractBenefitsExpense | Embedded derivatives        
Derivative [Line Items]        
Total gains (losses) for derivatives not designated as hedges (2,135) (887) (604) 116
Fair Value Hedging | Derivatives designated as hedges | Income Statement Location [Axis]: us-gaap:GainLossOnInvestments | Foreign currency swaps        
Derivative [Line Items]        
Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments 68 (681) 241 (1,013)
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge (80) 699 (254) 1,058
Derivative, Fair Value Hedge, Included in Effectiveness, Gain (Loss) (12) 18 (13) 45
Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Amortization Approach 0 0 0 0
Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Net 0 0 0 0
Fair Value Hedging | Derivatives designated as hedges | Income Statement Location [Axis]: us-gaap:GainLossOnInvestments | Interest rate swaps        
Derivative [Line Items]        
Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments (192) 65 (299) 194
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge 194 (49) 300 (174)
Derivative, Fair Value Hedge, Included in Effectiveness, Gain (Loss) 2 16 1 20
Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Amortization Approach 0 0 0 0
Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Net 0 0 0 0
Fair Value Hedging | Derivatives designated as hedges | Income Statement Location [Axis]: us-gaap:GainLossOnInvestments | Foreign currency forwards        
Derivative [Line Items]        
Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments 5 (235) 45 (350)
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge (6) 228 (42) 332
Derivative, Fair Value Hedge, Included in Effectiveness, Gain (Loss) (1) (7) 3 (18)
Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Amortization Approach 9 9 16 19
Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Net 0 0 0 0
Fair Value Hedging | Derivatives designated as hedges | Income Statement Location [Axis]: us-gaap:GainLossOnInvestments | Cross Currency Interest Rate Contract        
Derivative [Line Items]        
Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments (9) 344 (68) 481
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge 21 (330) 79 (464)
Derivative, Fair Value Hedge, Included in Effectiveness, Gain (Loss) 12 14 11 17
Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Amortization Approach 0 0 0 0
Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Net 0 0 0 0
Fair Value Hedging | Derivatives designated as hedges | Income Statement Location [Axis]: ahl:InterestSensitiveContractBenefitsExpense | Cross Currency Interest Rate Contract        
Derivative [Line Items]        
Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments 21 25 45 48
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge (21) (24) (44) (47)
Derivative, Fair Value Hedge, Included in Effectiveness, Gain (Loss) 0 1 1 1
Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Amortization Approach 0 0 0 0
Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Net $ 0 $ 0 $ 0 $ 0