Consolidated Statements of Comprehensive Income (Loss) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Other Comprehensive Income, Net of Tax, Changes In:
Net unrealized gains (losses) on investments with other-than-temporary impairments	$ 6	$ 84	$ 10
Net unrealized gains (losses) on other investments	(679)	339	365
Net unrealized gains (losses) on investments	(673)	423	375
Net unrealized gains (losses) on discontinued operations and other			(1)
Foreign currency translation adjustment	(11)	40	(15)
Pension and postretirement benefits	295	(112)	(208)
Other comprehensive income (loss), net of tax	(389)	351	151
Net income (loss)	937	628	628
Comprehensive income (loss)	548	979	779
Net unrealized (gains) losses on investments attributable to noncontrolling interests			(8)
Other comprehensive (income) loss attributable to noncontrolling interests			(8)
Net (income) loss attributable to noncontrolling interests			(16)
Comprehensive (income) loss attributable to noncontrolling interests			(24)
Total comprehensive income (loss) attributable to CNA	$ 548	$ 979	$ 755