Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Segment Reporting Information [Line Items]
Net income (loss)	$ (101)	$ 33	$ (5)	$ 534
Property & Casualty Commercial [Member]
Segment Reporting Information [Line Items]
Net income (loss)	149	118	338	441
Group Benefits [Member]
Segment Reporting Information [Line Items]
Net income (loss)	35	41	53	52
Consumer Markets [Member]
Segment Reporting Information [Line Items]
Net income (loss)	(50)	(172)	58	(64)
Individual Life [Member]
Segment Reporting Information [Line Items]
Net income (loss)	36	46	55	64
Retirement Plans [Member]
Segment Reporting Information [Line Items]
Net income (loss)	(2)	27	16	32
Mutual Funds [Member]
Segment Reporting Information [Line Items]
Net income (loss)	18	27	38	55
Life Other Operations [Member]
Segment Reporting Information [Line Items]
Net income (loss)	406	261	199	334
Property & Casualty Other Operations [Member]
Segment Reporting Information [Line Items]
Net income (loss)	(15)	(164)	12	(143)
Corporate [Member]
Segment Reporting Information [Line Items]
Net income (loss)	$ (678)	$ (151)	$ (774)	$ (237)