Schedule I - Condensed Financial Information of Registrant - Parent Company Only, Balance Sheets (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
ASSETS
Other assets	$ 2,443	$ 2,343
Total assets	78,316	79,586
LIABILITIES AND SHAREHOLDERS' EQUITY
Total liabilities	56,930	55,020
Shareholders' equity	18,518	19,204
Total liabilities and equity	78,316	79,586
Loews Corporation [Member]
ASSETS
Current assets, principally investment in short term instruments	2,050	2,755
Investments in securities	1,112	2,144
Investments in capital stocks of subsidiaries, at equity	17,556	16,303
Other assets	402	506
Total assets	21,120	21,708
LIABILITIES AND SHAREHOLDERS' EQUITY
Current liabilities	109	182
Long term debt	1,778	1,776
Deferred income tax and other	715	546
Total liabilities	2,602	2,504
Shareholders' equity	18,518	19,204
Total liabilities and equity	$ 21,120	$ 21,708