Shares and Stockholders' Equity - Reconciliation of the Denominator Calculations of Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Stockholders' Equity Note [Abstract]
Net income (loss) available to common stockholders – basic	$ (756)	$ 1,188
Deferred units of LNC stock in our deferred compensation plans	0	3
Net income (loss) available to common stockholders	$ (756)	$ 1,191
Weighted-average shares, as used in basic calculation (in shares)	171,321,440	170,049,994
Incremental common shares from assumed exercise or issuance of stock-based incentive compensation awards (in shares)	2,765,580	1,096,272
Average deferred compensation shares (in shares)	0	688,480
Weighted-average shares, as used in diluted calculation (in shares)	174,087,020	171,834,746
Net income (loss) per share:
Basic (in dollars per share)	$ (4.41)	$ 6.98
Diluted (in dollars per share)	$ (4.41)	$ 6.93