Segment Information Level 4 (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)
Segment Reporting Information [Line Items]
Number of company reporting segments			6
Segment Reporting Information, Operating Income (Loss) [Abstract]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ (40)	$ 216	$ 338	$ 539
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Earned premiums and fee income	3,956	3,885	7,884	7,734
Insurance Commissions and Fees	466	441	921	886
Net Investment Income (Loss)	715	735	1,443	1,431
Total Realized Investment Gains (Losses)	75	53	55	(102)
Other Income	23	23	42	43
Revenues	4,769	4,696	9,424	9,106
Property and Casualty, Commercial Insurance Product Line [Member]
Segment Reporting Information, Operating Income (Loss) [Abstract]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	258	237	489	462
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Earned premiums and fee income	1,729	1,659	3,427	3,292
Insurance Commissions and Fees	9	9	19	19
Property and Casualty, Personal Insurance Product Line [Member]
Segment Reporting Information, Operating Income (Loss) [Abstract]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	24	(50)	57	(27)
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Earned premiums and fee income	941	986	1,886	1,970
Insurance Commissions and Fees	0		0	0
Affinity Earned Premiums	800	817	1,600	1,600
Property & Casualty Other Operations [Member]
Segment Reporting Information, Operating Income (Loss) [Abstract]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	20	(154)	44	(137)
Group Insurance Policies [Member]
Segment Reporting Information, Operating Income (Loss) [Abstract]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	69	55	114	105
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Earned premiums and fee income	824	808	1,659	1,603
Mutual Fund [Member]
Segment Reporting Information, Operating Income (Loss) [Abstract]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	24	20	47	40
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Earned premiums and fee income	201	172	392	339
Life and Annuity Insurance Product Line [Member]
Segment Reporting Information, Operating Income (Loss) [Abstract]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	105	104	173	121
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Earned premiums and fee income	260	259	518	528
Corporate Segment [Member]
Segment Reporting Information, Operating Income (Loss) [Abstract]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(540)	4	(586)	(25)
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Insurance Commissions and Fees	1	1	2	2
Reclass from Commercial Lines to Personal Lines [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Other Income		3		0
Accident and Health Insurance Product Line [Member] | Property and Casualty, Commercial Insurance Product Line [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Earned premiums and fee income	820	775	1,633	1,534
General Liability [Member] | Property and Casualty, Commercial Insurance Product Line [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Earned premiums and fee income	152	148	300	291
Package Business [Member] | Property and Casualty, Commercial Insurance Product Line [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Earned premiums and fee income	326	314	640	622
Automobiles Commercial [Member] | Property and Casualty, Commercial Insurance Product Line [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Earned premiums and fee income	161	154	322	312
Professional Liability [Member] | Property and Casualty, Commercial Insurance Product Line [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Earned premiums and fee income	60	55	120	108
Surety Product Line [Member] | Property and Casualty, Commercial Insurance Product Line [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Earned premiums and fee income	58	54	113	107
Property Insurance Product Line [Member] | Property and Casualty, Commercial Insurance Product Line [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Earned premiums and fee income	152	159	299	318
Automobiles Consumer [Member] | Property and Casualty, Personal Insurance Product Line [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Earned premiums and fee income	660	687	1,322	1,372
Homeowners [Member] | Property and Casualty, Personal Insurance Product Line [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Earned premiums and fee income	281	299	564	598
Disability Insurance Policy [Member] | Group Insurance Policies [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Earned premiums and fee income	379	381	760	750
Life Insurance Product Line [Member] | Group Insurance Policies [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Earned premiums and fee income	394	376	793	751
Property & Casualty Other Operations [Member] | Group Insurance Policies [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Earned premiums and fee income	51	51	106	102
Non Proprietary [Member] | Mutual Fund [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Earned premiums and fee income	176	147	343	289
Proprietary [Member] | Life and Annuity Insurance Product Line [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Earned premiums and fee income	$ 25	$ 25	$ 49	$ 50