Goodwill Level 4 (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) segments	Dec. 31, 2015 USD ($)	Jul. 29, 2016 USD ($)	Dec. 31, 2014 USD ($)
Goodwill [Line Items]
Carrying Value	$ 567	$ 498
Business Acquisition, Goodwill, Expected Tax Deductible Amount			$ 69
Group Benefits [Member]
Goodwill [Line Items]
Goodwill impairment loss	0	0
Corporate Segment [Member]
Goodwill [Line Items]
Goodwill impairment loss		0
Property and Casualty, Personal Insurance Product Line [Member]
Goodwill [Line Items]
Carrying Value	119	119		$ 119
Business Acquisition, Goodwill, Expected Tax Deductible Amount			0
Goodwill impairment loss	$ 0
Mutual Funds [Member]
Goodwill [Line Items]
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		585
Goodwill, Impaired, Accumulated Impairment Loss		355		355
Carrying Value	$ 230	230
Business Acquisition, Goodwill, Expected Tax Deductible Amount			0
Commercial Lines [Member]
Goodwill [Line Items]
Carrying Value	38	0
Business Acquisition, Goodwill, Expected Tax Deductible Amount			38
Mutual Fund [Member]
Goodwill [Line Items]
Carrying Value	180	149
Business Acquisition, Goodwill, Expected Tax Deductible Amount			$ 31
Mutual Funds [Member]
Goodwill [Line Items]
Carrying Value	92	92		92
Group Benefits [Member]
Goodwill [Line Items]
Carrying Value	$ 138	$ 138		$ 138