v3.26.3
Derivative Instruments - Gains (Losses) on Derivatives Not Designated as Hedging (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Derivative [Line Items]        
Total gains (losses) for derivatives not designated as hedges $ 98 $ 369 $ 1,251 $ (1,433)
Income Statement Location [Axis]: us-gaap:GainLossOnInvestments        
Derivative [Line Items]        
Total gains (losses) for derivatives not designated as hedges (594) 1,629 1,163 (289)
Income Statement Location [Axis]: us-gaap:GainLossOnInvestments | Equity options        
Derivative [Line Items]        
Total gains (losses) for derivatives not designated as hedges 88 1,627 1,780 1,562
Income Statement Location [Axis]: us-gaap:GainLossOnInvestments | Futures        
Derivative [Line Items]        
Total gains (losses) for derivatives not designated as hedges (22) 123 44 107
Income Statement Location [Axis]: us-gaap:GainLossOnInvestments | Swap [Member]        
Derivative [Line Items]        
Total gains (losses) for derivatives not designated as hedges (704) (17) (853) (154)
Income Statement Location [Axis]: us-gaap:GainLossOnInvestments | Foreign currency swaps        
Derivative [Line Items]        
Total gains (losses) for derivatives not designated as hedges 61 108 614 (1,180)
Income Statement Location [Axis]: us-gaap:GainLossOnInvestments | Foreign currency forwards        
Derivative [Line Items]        
Total gains (losses) for derivatives not designated as hedges 449 (361) 237 (972)
Income Statement Location [Axis]: us-gaap:GainLossOnInvestments | Embedded derivatives        
Derivative [Line Items]        
Total gains (losses) for derivatives not designated as hedges (466) 149 (659) 348
Income Statement Location [Axis]: ahl:InterestSensitiveContractBenefitsExpense | Embedded derivatives        
Derivative [Line Items]        
Total gains (losses) for derivatives not designated as hedges 692 (1,260) 88 (1,144)
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 81 (9) 322 (1,022)
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge (76) 29 (330) 1,087
Derivative, Fair Value Hedge, Included in Effectiveness, Gain (Loss) 5 20 (8) 65
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 (877) 24 (1,176) 218
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge 803 (17) 1,103 (191)
Derivative, Fair Value Hedge, Included in Effectiveness, Gain (Loss) (74) 7 (73) 27
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 2 15 47 (335)
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge (2) (25) (44) 307
Derivative, Fair Value Hedge, Included in Effectiveness, Gain (Loss) 0 (10) 3 (28)
Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Amortization Approach 4 8 20 27
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 (15) (34) (83) 447
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge 33 13 112 (451)
Derivative, Fair Value Hedge, Included in Effectiveness, Gain (Loss) 18 (21) 29 (4)
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 22 23 67 71
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge (20) (23) (64) (70)
Derivative, Fair Value Hedge, Included in Effectiveness, Gain (Loss) 2 0 3 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