IT Transformation Costs by Segment (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2010
IT transformation cost	$ 36
CNA Specialty [Member]
IT transformation cost	8
CNA Commercial [Member]
IT transformation cost	15
Life and Group Non-Core [Member]
IT transformation cost	10
Corporate and Other Non-Core [Member]
IT transformation cost	$ 3