Condensed Consolidated Statements of Operations (Unaudited) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Revenues
Net earned premiums	$ 1,668	$ 1,595	$ 3,317	$ 3,210
Net investment income	470	517	1,118	1,137
Net realized investment gains (losses), net of participating policyholders’ interests:
Other-than-temporary impairment losses	(12)	(41)	(27)	(61)
Portion of other-than-temporary impairments recognized in Other comprehensive income (loss)	(11)	(21)	(23)	(42)
Net other-than-temporary impairment losses recognized in earnings	(23)	(62)	(50)	(103)
Other net realized investment gains (losses)	45	77	108	131
Net realized investment gains (losses), net of participating policyholders’ interests	22	15	58	28
Other revenues	86	71	154	138
Total revenues	2,246	2,198	4,647	4,513
Claims, Benefits and Expenses
Insurance claims and policyholders’ benefits	1,348	1,367	2,729	2,731
Amortization of deferred acquisition costs	309	286	604	583
Other operating expenses	316	326	635	603
Interest	43	43	85	89
Total claims, benefits and expenses	2,016	2,022	4,053	4,006
Income (loss) from continuing operations before income tax	230	176	594	507
Income tax (expense) benefit	(64)	(47)	(178)	(148)
Income (loss) from continuing operations, net of tax	166	129	416	359
Income (loss) from discontinued operations, net of income tax (expense) benefit of -, $0, - and $0				(1)
Net income (loss)	166	129	416	358
Net (income) loss attributable to noncontrolling interests		(5)		(14)
Net income (loss) attributable to CNA	166	124	416	344
Income (Loss) Attributable to Common Stockholders
Income (loss) from continuing operations attributable to CNA common stockholders	166	124	416	345
Income (loss) from discontinued operations attributable to CNA common stockholders				(1)
Income (loss) attributable to CNA common stockholders	$ 166	$ 124	$ 416	$ 344
Basic Earnings Per Share Attributable to CNA Common Stockholders
Income (loss) from continuing operations attributable to CNA common stockholders	$ 0.62	$ 0.46	$ 1.55	$ 1.28
Income (loss) from discontinued operations attributable to CNA common stockholders	$ 0.00	$ 0.00	$ 0.00	$ 0.00
Income attributable to CNA common stockholders	$ 0.62	$ 0.46	$ 1.55	$ 1.28
Diluted Earnings Per Share Attributable to CNA Common Stockholders
Income (loss) from continuing operations attributable to CNA common stockholders	$ 0.62	$ 0.46	$ 1.54	$ 1.28
Income (loss) from discontinued operations attributable to CNA common stockholders
Income attributable to CNA common stockholders	$ 0.62	$ 0.46	$ 1.54	$ 1.28
Dividends per share	$ 0.15	$ 0.10	$ 0.30	$ 0.20
Weighted Average Outstanding Common Stock and Common Stock Equivalents
Basic	269.4	269.3	269.4	269.3
Diluted	269.8	269.6	269.7	269.6