v3.26.1
Derivative Instruments - Change in Our Unrealized Gain on Derivative Instruments in AOCI (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Change in our unrealized gain on derivative instruments in accumulated OCI        
Balance as of beginning-of-period     $ 10,906  
Balance as of end-of-period $ 11,349 $ 9,548 11,349 $ 9,548
Interest rate contracts | Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss | Qualifying Hedges        
Change in our unrealized gain on derivative instruments in accumulated OCI        
Hedged items 0 0 0 0
Derivatives designated as hedging instruments 0 0 0 0
Interest rate contracts | Location, Statement of Income, Balance [Axis]: us-gaap:NetInvestmentIncome | Qualifying Hedges        
Change in our unrealized gain on derivative instruments in accumulated OCI        
Hedged items (4) 3 (5) 14
Derivatives designated as hedging instruments 4 (3) 5 (14)
Interest rate contracts | Location, Statement of Income, Balance [Axis]: lnc:InterestExpenseDebtIncludingGainLossOnExtinguishmentOfDebt | Qualifying Hedges        
Change in our unrealized gain on derivative instruments in accumulated OCI        
Hedged items 0 (1) (2) (17)
Derivatives designated as hedging instruments 0 1 2 17
Foreign currency contracts | Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss | Qualifying Hedges        
Change in our unrealized gain on derivative instruments in accumulated OCI        
Hedged items 0 0 0 0
Derivatives designated as hedging instruments 0 0 0 0
Foreign currency contracts | Location, Statement of Income, Balance [Axis]: us-gaap:NetInvestmentIncome | Qualifying Hedges        
Change in our unrealized gain on derivative instruments in accumulated OCI        
Hedged items 0 2 (1) 3
Derivatives designated as hedging instruments 0 (2) 1 (3)
Foreign currency contracts | Location, Statement of Income, Balance [Axis]: lnc:InterestExpenseDebtIncludingGainLossOnExtinguishmentOfDebt | Qualifying Hedges        
Change in our unrealized gain on derivative instruments in accumulated OCI        
Hedged items 0 0 0 0
Derivatives designated as hedging instruments 0 0 0 0
Unrealized Gain (Loss) on Derivative Instruments        
Change in our unrealized gain on derivative instruments in accumulated OCI        
Balance as of beginning-of-period     450 638
Income tax benefit (expense)     (19) 57
Reclassification adjustment for gains (losses) included in net income (loss)     36 39
Income tax benefit (expense)     (8) (8)
Balance as of end-of-period $ 486 $ 396 486 396
Unrealized Gain (Loss) on Derivative Instruments | Interest rate contracts | Location, Statement of Income, Balance [Axis]: us-gaap:NetInvestmentIncome        
Change in our unrealized gain on derivative instruments in accumulated OCI        
Reclassification adjustment for gains (losses) included in net income (loss)     0 1
Unrealized Gain (Loss) on Derivative Instruments | Interest rate contracts | Location, Statement of Income, Balance [Axis]: lnc:InterestExpenseDebtIncludingGainLossOnExtinguishmentOfDebt        
Change in our unrealized gain on derivative instruments in accumulated OCI        
Reclassification adjustment for gains (losses) included in net income (loss)     4 8
Unrealized Gain (Loss) on Derivative Instruments | Foreign currency contracts | Location, Statement of Income, Balance [Axis]: us-gaap:DebtAndEquitySecuritiesRealizedGainLoss        
Change in our unrealized gain on derivative instruments in accumulated OCI        
Reclassification adjustment for gains (losses) included in net income (loss)     1 3
Unrealized Gain (Loss) on Derivative Instruments | Foreign currency contracts | Location, Statement of Income, Balance [Axis]: us-gaap:NetInvestmentIncome        
Change in our unrealized gain on derivative instruments in accumulated OCI        
Reclassification adjustment for gains (losses) included in net income (loss)     31 27
Unrealized holding gains (losses) arising during the period - cash flow hedges        
Change in our unrealized gain on derivative instruments in accumulated OCI        
Changes arising during the year     (4) 206
Unrealized holding gains (losses) arising during the period - cash flow hedges | Interest rate contracts        
Change in our unrealized gain on derivative instruments in accumulated OCI        
Changes arising during the year     (13) 37
Unrealized holding gains (losses) arising during the period - cash flow hedges | Foreign currency contracts        
Change in our unrealized gain on derivative instruments in accumulated OCI        
Changes arising during the year     9 169
Change in foreign currency exchange rate adjustment        
Change in our unrealized gain on derivative instruments in accumulated OCI        
Changes arising during the year     $ 87 $ (474)