Condensed Consolidated Statements of Operations (Unaudited) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Revenues
Net earned premiums	$ 1,781	$ 1,732	$ 5,098	$ 4,942
Net investment income	601	394	1,719	1,531
Net realized investment gains (losses), net of participating policyholders’ interests:
Other-than-temporary impairment losses	(62)	(75)	(89)	(136)
Portion of other-than-temporary impairments recognized in Other comprehensive income (loss)	(2)	(2)	(25)	(44)
Net other-than-temporary impairment losses recognized in earnings	(64)	(77)	(114)	(180)
Other net realized investment gains (losses)	72	50	180	181
Net realized investment gains (losses), net of participating policyholders’ interests	8	(27)	66	1
Other revenues	76	76	230	214
Total revenues	2,466	2,175	7,113	6,688
Claims, Benefits and Expenses
Insurance claims and policyholders’ benefits	1,435	1,400	4,164	4,131
Amortization of deferred acquisition costs	333	297	937	880
Other operating expenses	341	311	976	914
Interest	43	43	128	132
Total claims, benefits and expenses	2,152	2,051	6,205	6,057
Income (loss) from continuing operations before income tax	314	124	908	631
Income tax (expense) benefit	(93)	(48)	(271)	(196)
Income (loss) from continuing operations	221	76	637	435
Income (loss) from discontinued operations, net of income tax (expense) benefit of -, -, - and $0				(1)
Net income (loss)	221	76	637	434
Net (income) loss attributable to noncontrolling interests		(1)		(15)
Net income (loss) attributable to CNA	221	75	637	419
Income (Loss) Attributable to CNA Common Stockholders
Income (loss) from continuing operations attributable to CNA common stockholders	221	75	637	420
Income (loss) from discontinued operations attributable to CNA common stockholders				(1)
Income (loss) attributable to CNA common stockholders	$ 221	$ 75	$ 637	$ 419
Basic Earnings Per Share Attributable to CNA Common Stockholders
Income (loss) from continuing operations attributable to CNA common stockholders	$ 0.82	$ 0.28	$ 2.37	$ 1.56
Income (loss) from discontinued operations attributable to CNA common stockholders
Income (loss) attributable to CNA common stockholders	$ 0.82	$ 0.28	$ 2.37	$ 1.56
Diluted Earnings Per Share Attributable to CNA Common Stockholders
Income (loss) from continuing operations attributable to CNA common stockholders	$ 0.82	$ 0.28	$ 2.36	$ 1.56
Income (loss) from discontinued operations attributable to CNA common stockholders
Income (loss) attributable to CNA common stockholders	$ 0.82	$ 0.28	$ 2.36	$ 1.56
Dividends per share	$ 0.15	$ 0.10	$ 0.45	$ 0.30
Weighted Average Outstanding Common Stock and Common Stock Equivalents
Basic	269.4	269.3	269.4	269.3
Diluted	269.8	269.6	269.8	269.6