Consolidated Statements of Stockholders' Equity (USD $) In Millions	Total	Preferred stock [Member]	Common stock [Member]	Additional paid-in capital [Member]	Retained earnings [Member]	Accumulated other comprehensive income (loss) [Member]	Treasury stock [Member]	Notes receivable for the issuance of common stock [Member]	Parent Company [Member]	Noncontrolling interest [Member]
Balance at Dec. 31, 2009 (Scenario, Previously Reported [Member])				$ 2,177	$ 7,264	$ (325)				$ 506
Balance at Dec. 31, 2009		1,000	683	2,177	7,191	(325)	(109)	(30)		499
Net income (loss)	759				691					68
Other comprehensive income (loss)	661					649				12
Dividends paid to common stockholders
Stock-based compensation				1			4
(Increase) Decrease in notes receivable from the issuance of common stock								4
Other				22						(16)
Dividends paid to Loews Corporation for 2008 Senior Preferred					(76)
Redemption of 2008 Senior Preferred		(1,000)
Cumulative effect adjustment from change in accounting guidance, net of tax (Accounting standards update 2010-26 [Member])					(73)					(7)
Cumulative effect adjustment from change in accounting guidance, net of tax (Accounting Standards Update 2010-11 [Member])					(2)	2
Acquisition of CNA Surety noncontrolling interest
Disposition of FICOH ownership interest
Balance at Dec. 31, 2010 (Scenario, Previously Reported [Member])				2,200	7,876	326				570
Balance at Dec. 31, 2010	11,445		683	2,200	7,804	326	(105)	(26)	10,882	563
Net income (loss)	628				612					16
Other comprehensive income (loss)	151					143				8
Dividends paid to common stockholders					(108)
Stock-based compensation				4			3
(Increase) Decrease in notes receivable from the issuance of common stock								4
Other				2						(11)
Dividends paid to Loews Corporation for 2008 Senior Preferred
Redemption of 2008 Senior Preferred
Cumulative effect adjustment from change in accounting guidance, net of tax (Accounting standards update 2010-26 [Member])					(72)					(7)
Cumulative effect adjustment from change in accounting guidance, net of tax (Accounting Standards Update 2010-11 [Member])
Acquisition of CNA Surety noncontrolling interest				(65)		19				(429)
Disposition of FICOH ownership interest						(8)				(147)
Balance at Dec. 31, 2011 (Scenario, Previously Reported [Member])				2,146	8,382	470
Balance at Dec. 31, 2011	11,488		683	2,141	8,308	480	(102)	(22)	11,488
Net income (loss)	628				628
Other comprehensive income (loss)	351					351
Dividends paid to common stockholders					(162)
Stock-based compensation				5			3
(Increase) Decrease in notes receivable from the issuance of common stock								1
Other
Dividends paid to Loews Corporation for 2008 Senior Preferred
Redemption of 2008 Senior Preferred
Cumulative effect adjustment from change in accounting guidance, net of tax (Accounting standards update 2010-26 [Member])				(5)	(74)	10
Cumulative effect adjustment from change in accounting guidance, net of tax (Accounting Standards Update 2010-11 [Member])
Acquisition of CNA Surety noncontrolling interest
Disposition of FICOH ownership interest
Balance at Dec. 31, 2012	$ 12,314		$ 683	$ 2,146	$ 8,774	$ 831	$ (99)	$ (21)	$ 12,314