Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions					12 Months Ended
	Jul. 28, 2022	Feb. 01, 2021	Jan. 14, 2021	Feb. 18, 2020	Dec. 31, 2021	Dec. 31, 2023	Dec. 31, 2022	Oct. 14, 2022	Jul. 07, 2020
Sale of Stock [Line Items]
Common stock, authorized (in shares)						200,000,000	200,000,000		200,000,000
Common stock, par value (usd per share)						$ 0.00001	$ 0.00001		$ 0.00001
Preferred stock, authorized (in shares)						10,000,000	10,000,000		10,000,000
Preferred stock, par value (usd per share)						$ 0.00001	$ 0.00001		$ 0.00001
Preferred stock, shares issued (in shares)						0	0
Preferred stock, shares outstanding (in shares)						0	0
Omnibus Agreement
Sale of Stock [Line Items]
Class of warrant issued of common stock (in shares)								3,352,025
Exercise price (usd per share)								$ 0.01
Warrant vesting period								5 years
The Lemonade Foundation | Affiliated entity
Sale of Stock [Line Items]
Contribution to the Lemonade Foundation (in shares)				500,000	500,000
Metromile
Sale of Stock [Line Items]
Shares issued for acquisition (in shares)	6,901,934
Follow-on Offering
Sale of Stock [Line Items]
Common stock sold (in shares)			3,300,000
Net proceeds from sale			$ 525.7
Follow-on Offering, Selling Shareholders
Sale of Stock [Line Items]
Common stock sold (in shares)			1,524,314
Follow-on Offering, Selling Shareholders | The Lemonade Foundation
Sale of Stock [Line Items]
Common stock sold (in shares)			100,000
Underwriter's option
Sale of Stock [Line Items]
Common stock sold (in shares)		718,647
Net proceeds from sale		$ 114.6