CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) [Abstract]
Net income (loss)	$ (1,291)	$ 871	$ 706
Other comprehensive income (loss), after tax Changes in:
Net unrealized gains (losses) on investments with an allowance for credit losses
Net unrealized gains (losses) on other investments	720	948	(812)
Total unrealized gains (losses) on investments	720	948	(812)
Unrealized gains (losses) on cash flow hedges	(17)	(11)	6
Pension and postretirement benefits	(24)	(68)	(2)
Foreign currency translation	48	42	(84)
Other comprehensive income (loss)	727	911	(892)
Comprehensive income (loss)	(564)	1,782	(186)
Amounts attributable to noncontrolling interests	282	(38)	25
Total comprehensive income (loss) attributable to Loews Corporation	$ (282)	$ 1,744	$ (161)