Schedule I - Condensed Financial Information of Registrant - Parent Company Only, Statements of Cash Flows (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Activities:
Net income	$ 716	$ 287	$ 962
Adjustments to reconcile net income to net cash provided (used) by operating activities:
Equity method investees	221	182	64
Provision for deferred income taxes	102	(225)	11
Changes in operating assets and liabilities, net:
Receivables	24	120	738
Trading securities	(528)	674	(129)
Investing Activities:
Change in investments, primarily short term	158	120	1,396
Other	158	(172)	(108)
Financing Activities:
Dividends paid	(84)	(90)	(95)
Issuance of common stock		7	6
Purchases of treasury shares	(134)	(1,265)	(622)
Principal payments in debt	(3,418)	(1,929)	(2,269)
Issuance of debt	3,614	1,828	2,004
Other	(2)	4	16
Net change in cash	(113)	76	70
Cash, beginning of year	440	364	294
Cash, end of year	327	440	364
Loews Corporation [Member]
Operating Activities:
Net income	654	260	591
Adjustments to reconcile net income to net cash provided (used) by operating activities:
Equity method investees	115	488	95
Provision for deferred income taxes	10	113	(62)
Changes in operating assets and liabilities, net:
Receivables	2	(6)	(2)
Accounts payable and accrued liabilities	52	71	200
Trading securities	(614)	718	(269)
Other, net	(15)	(8)	(23)
Net cash flow operating activities	204	1,636	530
Investing Activities:
Investments in and advances to subsidiaries	50	(285)	130
Change in investments, primarily short term	(127)		7
Other	(2)	(4)	(2)
Net cash flow investing activities	(79)	(289)	135
Financing Activities:
Dividends paid	(84)	(90)	(95)
Issuance of common stock		7	6
Purchases of treasury shares	(134)	(1,265)	(622)
Principal payments in debt	(400)
Issuance of debt	495
Other	(2)	1	2
Net cash flow financing activities	$ (125)	$ (1,347)	(709)
Net change in cash			(44)
Cash, beginning of year			$ 44