Business Segments (Consolidated Revenues And Income (Loss) Attributable To Loews Corporation By Business Segment) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012 mi	Mar. 31, 2011
Segment Reporting Information [Line Items]
Revenues	$ 3,744	$ 3,668
Income (loss) before income tax and noncontrolling interests	741	757
Net income (loss) - Loews	367	379
Investment gains (losses) included in revenues and income (loss) before income tax and noncontrolling interests	32	23
Investment gains (losses) included in net income (loss)	19	12
Number of offshore drilling rigs	48
Number of countries where drilling rigs are located	12
Miles of natural gas pipeline	14,300
Acres of holding rights on minerals	700,000
Number of productive wells	6,000
Total number of parent hotels owned	17
Number of parent hotels in the United States	15
Number of parent hotels in Canada	2
CNA Specialty [Member]
Segment Reporting Information [Line Items]
Revenues	945	891
Income (loss) before income tax and noncontrolling interests	209	214
Net income (loss) - Loews	125	121
Investment gains (losses) included in revenues and income (loss) before income tax and noncontrolling interests	8	8
Investment gains (losses) included in net income (loss)	5	5
CNA Commercial [Member]
Segment Reporting Information [Line Items]
Revenues	1,088	1,094
Income (loss) before income tax and noncontrolling interests	227	212
Net income (loss) - Loews	131	125
Investment gains (losses) included in revenues and income (loss) before income tax and noncontrolling interests	11	17
Investment gains (losses) included in net income (loss)	6	9
Life And Group Non-Core [Member]
Segment Reporting Information [Line Items]
Revenues	350	326
Income (loss) before income tax and noncontrolling interests	(37)	(48)
Net income (loss) - Loews	(10)	(19)
Investment gains (losses) included in revenues and income (loss) before income tax and noncontrolling interests	13	(4)
Investment gains (losses) included in net income (loss)	7	(2)
Other [Member]
Segment Reporting Information [Line Items]
Revenues	18	13
Income (loss) before income tax and noncontrolling interests	(33)	(46)
Net income (loss) - Loews	(20)	(28)
Investment gains (losses) included in revenues and income (loss) before income tax and noncontrolling interests		1
Investment gains (losses) included in net income (loss)	1
Total CNA Financial [Member]
Segment Reporting Information [Line Items]
Revenues	2,401	2,324
Income (loss) before income tax and noncontrolling interests	366	332
Net income (loss) - Loews	226	199
Investment gains (losses) included in revenues and income (loss) before income tax and noncontrolling interests	32	22
Diamond Offshore [Member]
Segment Reporting Information [Line Items]
Revenues	796	809
Income (loss) before income tax and noncontrolling interests	252	296
Net income (loss) - Loews	87	117
Boardwalk Pipeline [Member]
Segment Reporting Information [Line Items]
Revenues	314	311
Income (loss) before income tax and noncontrolling interests	92	82
Net income (loss) - Loews	35	33
HighMount [Member]
Segment Reporting Information [Line Items]
Revenues	76	104
Income (loss) before income tax and noncontrolling interests	(34)	29
Net income (loss) - Loews	(22)	19
Loews Hotels [Member]
Segment Reporting Information [Line Items]
Revenues	80	80
Income (loss) before income tax and noncontrolling interests	7	3
Net income (loss) - Loews	4	2
Corporate And Other [Member]
Segment Reporting Information [Line Items]
Revenues	77	40
Income (loss) before income tax and noncontrolling interests	58	15
Net income (loss) - Loews	37	9
Investment gains (losses) included in revenues and income (loss) before income tax and noncontrolling interests		$ 1