CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Common Stock Held in Treasury [Member]	Noncontrolling Interests [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Retained Earnings [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Accumulated Other Comprehensive Income (Loss) [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Noncontrolling Interests [Member]	Cumulative Effect, Period of Adoption, Adjusted Balance [Member]	Cumulative Effect, Period of Adoption, Adjusted Balance [Member] Common Stock [Member]	Cumulative Effect, Period of Adoption, Adjusted Balance [Member] Additional Paid-in Capital [Member]	Cumulative Effect, Period of Adoption, Adjusted Balance [Member] Retained Earnings [Member]	Cumulative Effect, Period of Adoption, Adjusted Balance [Member] Accumulated Other Comprehensive Income (Loss) [Member]	Cumulative Effect, Period of Adoption, Adjusted Balance [Member] Common Stock Held in Treasury [Member]	Cumulative Effect, Period of Adoption, Adjusted Balance [Member] Noncontrolling Interests [Member]
Balance at Dec. 31, 2017	$ 24,566	$ 3	$ 3,151	$ 16,096	$ (26)	$ (20)	$ 5,362	$ (91)	$ (43)	$ (28)	$ (20)	$ 24,475	$ 3	$ 3,151	$ 16,053	$ (54)	$ (20)	$ 5,342
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Net income (loss)	706			636			70
Other comprehensive income (loss)	(892)				(797)		(95)
Dividends paid ($0.25 per share)	(201)			(80)
Dividends paid ($0.25 per share)							(121)
Purchase of Boardwalk Pipelines common units	(1,718)		658		(29)		(2,347)
Purchases of Loews Corporation treasury stock	(1,011)					(1,011)
Retirement of treasury stock	0		(195)	(831)		1,026
Stock-based compensation	31		19				12
Other	(4)		(6)	(5)			7
Balance at Dec. 31, 2018	21,386	3	3,627	15,773	(880)	(5)	2,868
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Net income (loss)	871			932			(61)
Other comprehensive income (loss)	911				812		99
Dividends paid ($0.25 per share)	(174)			(76)
Dividends paid ($0.25 per share)							(98)
Purchases of subsidiary stock from noncontrolling interests	(23)						(23)
Purchases of Loews Corporation treasury stock	(1,059)					(1,059)
Retirement of treasury stock	0		(248)	(803)		1,051
Stock-based compensation	27		4				23
Other	(9)		(9)	(3)			3
Balance at Dec. 31, 2019	21,930	3	3,374	15,823	(68)	(13)	2,811	$ (5)	$ (5)			$ 21,925	$ 3	$ 3,374	$ 15,818	$ (68)	$ (13)	$ 2,811
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Net income (loss)	(1,291)			(931)			(360)
Other comprehensive income (loss)	727				649		78
Dividends paid ($0.25 per share)	(169)			(70)
Dividends paid ($0.25 per share)							(99)
Deconsolidation of Diamond Offshore	(1,087)						(1,087)
Purchases of subsidiary stock from noncontrolling interests	(37)		5				(42)
Purchases of Loews Corporation treasury stock	(917)					(917)
Retirement of treasury stock	0		(256)	(667)		923
Stock-based compensation	26		8				18
Other	4		2				2
Balance at Dec. 31, 2020	$ 19,181	$ 3	$ 3,133	$ 14,150	$ 581	$ (7)	$ 1,321