Goodwill Level 4 (Details) $ in Millions		12 Months Ended
		Dec. 31, 2015 USD ($) segments	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Goodwill [Line Items]
Gross		$ 853
Goodwill, Impaired, Accumulated Impairment Loss		(355)
Carrying Value		498	$ 498
Goodwill, Written off Related to Sale of Business Unit				$ 156
Group Benefits [Member]
Goodwill [Line Items]
Goodwill impairment loss		0	$ 0
Annual Impairment Test Margin, Percent			10.00%
Corporate Segment [Member]
Goodwill [Line Items]
Goodwill impairment loss			$ 0
Property and Casualty, Personal Insurance Product Line [Member]
Goodwill [Line Items]
Gross		119
Goodwill, Impaired, Accumulated Impairment Loss		0
Carrying Value		119
Goodwill impairment loss		0
Mutual Funds [Member]
Goodwill [Line Items]
Gross		149
Goodwill, Impaired, Accumulated Impairment Loss		0
Carrying Value		$ 149
Individual Life [Member]
Goodwill [Line Items]
Goodwill impairment loss			0
Retirement Plans [Member]
Goodwill [Line Items]
Goodwill impairment loss			$ 0
Annual Impairment Test Margin, Percent		10.00%
Number of Company Reporting Segments which completed interim impairment test | segments		2
Corporate [Member]
Goodwill [Line Items]
Gross		$ 585
Goodwill, Impaired, Accumulated Impairment Loss	[1]	(355)
Carrying Value		230
Group Benefits [Member]
Goodwill [Line Items]
Carrying Value		138
Mutual Funds [Member]
Goodwill [Line Items]
Carrying Value		$ 92

[1] Carrying value as of December 31, 2015 and 2014 includes $138 and $92 for the Group Benefits and Mutual Funds reporting units, respectively.