Consolidating Financial Information (Consolidating Balance Sheet Information) (Details) (USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2010	Dec. 31, 2009
Investments	$ 48,884	$ 48,907
Cash	148	120	91	190
Receivables	10,133	10,142
Property, plant and equipment	12,456	12,636
Deferred income taxes		289
Goodwill	856	856
Investment in capital stocks of subsidiaries
Other assets	2,036	1,798
Deferred acquisition costs of insurance subsidiaries	1,106	1,079
Separate account business	450	450
Total assets	76,069	76,277
Insurance reserves	37,792	37,590
Short term debt	6	647
Payable to brokers	558	685
Long term debt	9,163	8,830
Deferred income taxes	638	562
Other liabilities	3,979	4,407
Separate account business	450	450
Total liabilities	52,586	53,171
Total shareholders' equity	18,953	18,450
Noncontrolling interests	4,530	4,656
Total equity	23,483	23,106	22,727	21,085
Total liabilities and equity	76,069	76,277
CNA Financial [Member]
Investments	43,377	42,655
Cash	84	77
Receivables	9,252	9,224
Property, plant and equipment	258	286
Deferred income taxes	406	699
Goodwill	86	86
Investment in capital stocks of subsidiaries
Other assets	707	724
Deferred acquisition costs of insurance subsidiaries	1,106	1,079
Separate account business	450	450
Total assets	55,726	55,280
Insurance reserves	37,792	37,590
Short term debt		400
Payable to brokers	362	239
Long term debt	2,648	2,251
Deferred income taxes
Other liabilities	2,773	2,877
Separate account business	450	450
Total liabilities	44,025	43,807
Total shareholders' equity	10,416	9,838
Noncontrolling interests	1,285	1,635
Total equity	11,701	11,473
Total liabilities and equity	55,726	55,280
Diamond Offshore [Member]
Investments	945	1,055
Cash	36	22
Receivables	629	671
Property, plant and equipment	4,166	4,291
Deferred income taxes
Goodwill	20	20
Investment in capital stocks of subsidiaries
Other assets	944	678
Deferred acquisition costs of insurance subsidiaries
Separate account business
Total assets	6,740	6,737
Insurance reserves
Short term debt
Payable to brokers
Long term debt	1,488	1,487
Deferred income taxes	518	533
Other liabilities	570	831
Separate account business
Total liabilities	2,576	2,851
Total shareholders' equity	2,112	1,972
Noncontrolling interests	2,052	1,914
Total equity	4,164	3,886
Total liabilities and equity	6,740	6,737
HighMount [Member]
Investments	113	128
Cash	11	2
Receivables	81	109
Property, plant and equipment	1,386	1,350
Deferred income taxes	536	548
Goodwill	584	584
Investment in capital stocks of subsidiaries
Other assets	21	27
Deferred acquisition costs of insurance subsidiaries
Separate account business
Total assets	2,732	2,748
Insurance reserves
Short term debt
Payable to brokers	107	115
Long term debt	1,100	1,100
Deferred income taxes
Other liabilities	64	93
Separate account business
Total liabilities	1,271	1,308
Total shareholders' equity	1,461	1,440
Noncontrolling interests
Total equity	1,461	1,440
Total liabilities and equity	2,732	2,748
Boardwalk Pipeline [Member]
Investments	50	52
Cash	5	7
Receivables	83	71
Property, plant and equipment	6,263	6,326
Deferred income taxes
Goodwill	163	163
Investment in capital stocks of subsidiaries
Other assets	325	339
Deferred acquisition costs of insurance subsidiaries
Separate account business
Total assets	6,889	6,958
Insurance reserves
Short term debt
Payable to brokers		2
Long term debt	3,122	3,252
Deferred income taxes	458	410
Other liabilities	348	372
Separate account business
Total liabilities	3,928	4,036
Total shareholders' equity	1,768	1,815
Noncontrolling interests	1,193	1,107
Total equity	2,961	2,922
Total liabilities and equity	6,889	6,958
Loews Hotels [Member]
Investments	60	57
Cash	10	10
Receivables	43	33
Property, plant and equipment	339	347
Deferred income taxes
Goodwill	3	3
Investment in capital stocks of subsidiaries
Other assets	29	24
Deferred acquisition costs of insurance subsidiaries
Separate account business
Total assets	484	474
Insurance reserves
Short term debt	6	72
Payable to brokers
Long term debt	213	148
Deferred income taxes	55	54
Other liabilities	22	21
Separate account business
Total liabilities	296	295
Total shareholders' equity	188	179
Noncontrolling interests
Total equity	188	179
Total liabilities and equity	484	474
Corporate And Other [Member]
Investments	4,339	4,960
Cash	2	2
Receivables	148	169
Property, plant and equipment	44	36
Investment in capital stocks of subsidiaries	16,006	15,314
Other assets	10	6
Total assets	20,549	20,487
Short term debt		175
Payable to brokers	89	329
Long term debt	692	692
Deferred income taxes	549	523
Other liabilities	205	248
Total liabilities	1,535	1,967
Total shareholders' equity	19,014	18,520
Total equity	19,014	18,520
Total liabilities and equity	20,549	20,487
Eliminations [Member]
Receivables	(103)	(135)
Deferred income taxes	(942)	(958)
Investment in capital stocks of subsidiaries	(16,006)	(15,314)
Total assets	(17,051)	(16,407)
Long term debt	(100)	(100)
Deferred income taxes	(942)	(958)
Other liabilities	(3)	(35)
Total liabilities	(1,045)	(1,093)
Total shareholders' equity	(16,006)	(15,314)
Total equity	(16,006)	(15,314)
Total liabilities and equity	$ (17,051)	$ (16,407)