Basis of Presentation - Adoption on Consolidated Condensed Statement of Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Changes in: Net unrealized losses on other investments	$ 670	$ (2,643)
Total unrealized losses on investments	662	(2,647)
Impact of changes in discount rates used to measure long-duration contract liabilities	(396)	1,635
Other comprehensive loss	289	(1,002)
Comprehensive loss	693	(650)
Amounts attributable to noncontrolling interests	(60)	76
Total comprehensive loss attributable to Loews Corporation	$ 633	(574)
As Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Changes in: Net unrealized losses on other investments		(1,611)
Total unrealized losses on investments		(1,615)
Other comprehensive loss		(1,605)
Comprehensive loss		(1,235)
Amounts attributable to noncontrolling interests		136
Total comprehensive loss attributable to Loews Corporation		(1,099)
Effect of Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Changes in: Net unrealized losses on other investments		(1,032)
Total unrealized losses on investments		(1,032)
Impact of changes in discount rates used to measure long-duration contract liabilities		1,635
Other comprehensive loss		603
Comprehensive loss		585
Amounts attributable to noncontrolling interests		(60)
Total comprehensive loss attributable to Loews Corporation		$ 525