Investments - Narrative (Details) $ in Millions	3 Months Ended		12 Months Ended
Investments - Narrative (Details) $ in Millions	Mar. 31, 2025 USD ($) investment	Mar. 31, 2024 USD ($)	Dec. 31, 2024 USD ($) investment
Investments [Line Items]
Decrease in gross AFS securities unrealized losses	$ 514
Losses from loan modifications	$ 5	$ 0
Number of partnerships in alternative investment portfolio \| investment	351		351
Alternative investments as a percentage of overall invested assets	3.00%		3.00%
Investment commitments	$ 4,600
Investment commitments for limited partnerships	3,500
Investment commitments for mortgage loans on real estate	828
Investment commitments for private placements	275
Derivative Counterparties
Investments [Line Items]
Fair value of collateral received that we are permitted to sell or re-pledge	2,200
Fair value of securities received as collateral that have been resold or repledged	64
Corporate bonds
Investments [Line Items]
Amortized cost of portfolio rated below investment grade	2,700		$ 2,700
Fair value of portfolio rated below investment grade	2,600		2,700
White Chapel V LLC \| MBS
Investments [Line Items]
Fair value, concentration of risk	1,300		1,500
White Chapel LLC \| MBS
Investments [Line Items]
Fair value, concentration of risk	1,100		1,100
Financial Service \| Securities Investment
Investments [Line Items]
Fair value, concentration of risk	16,100		16,200
Consumer Non-Cyclical Industry \| Securities Investment
Investments [Line Items]
Fair value, concentration of risk	$ 10,900		$ 10,700
Credit Assessment \| Reinsurer Concentration Risk \| Corporate bonds
Investments [Line Items]
Percentage of fair value rated as investment grade	96.00%		96.00%
Investments \| Lender Concentration Risk \| White Chapel V LLC \| MBS
Investments [Line Items]
Concentration risk	1.00%		1.00%
Investments \| Lender Concentration Risk \| White Chapel LLC \| MBS
Investments [Line Items]
Concentration risk	1.00%		1.00%
Investments \| Lender Concentration Risk \| Financial Service \| Securities Investment
Investments [Line Items]
Concentration risk	13.00%		13.00%
Investments \| Lender Concentration Risk \| Consumer Non-Cyclical Industry \| Securities Investment
Investments [Line Items]
Concentration risk	9.00%		9.00%

LINCOLN NATIONAL LIFE INSURANCE CO /IN/ 10-Q