Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Segment Reporting Information [Line Items]
Net income	$ 96	$ 501
Property & Casualty Commercial [Member]
Segment Reporting Information [Line Items]
Net income	189	323
Group Benefits [Member]
Segment Reporting Information [Line Items]
Net income	18	11
Consumer Markets [Member]
Segment Reporting Information [Line Items]
Net income	108	108
Individual Annuity [Member]
Segment Reporting Information [Line Items]
Net income	198	143
Individual Life [Member]
Segment Reporting Information [Line Items]
Net income	19	18
Retirement Plans [Member]
Segment Reporting Information [Line Items]
Net income	18	5
Mutual Funds [Member]
Segment Reporting Information [Line Items]
Net income	20	28
Life Other Operations [Member]
Segment Reporting Information [Line Items]
Net income	(405)	(70)
Property & Casualty Other Operations [Member]
Segment Reporting Information [Line Items]
Net income	27	21
Corporate [Member]
Segment Reporting Information [Line Items]
Net income	$ (96)	$ (86)