Fair Value Measurements (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
US Treasury and Government [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance	$ 15	$ 20	$ 15	$ 20
Total realized/unrealized gains (losses) included in Net income	0	0	0	0
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	0	(1)	0	(1)
Purchases and issuances	0	0	0	0
Sales and settlements	0	0	0	0
Transfer into Level 3	0	0	0	0
Transfer out of Level 3	0	0	0	0
Financial assets, Ending Balance	15	19	15	19
States, municipalities and political subdivisions [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance	61	63	61	58
Total realized/unrealized gains (losses) included in Net income	(1)	0	(1)	0
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	(1)	(1)	(1)	(2)
Purchases and issuances	0	0	0	10
Sales and settlements	0	0	0	0
Transfer into Level 3	7	0	7	0
Transfer out of Level 3	0	0	0	(4)
Financial assets, Ending Balance	66	62	66	62
Residential Mortgage Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance	256	329	316	371
Total realized/unrealized gains (losses) included in Net income	0	1	3	5
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	(1)	8	5	7
Purchases and issuances	8	0	8	6
Sales and settlements	(8)	(13)	(23)	(42)
Transfer into Level 3	20	43	58	68
Transfer out of Level 3	(12)	(47)	(104)	(94)
Financial assets, Ending Balance	263	321	263	321
Commercial Mortgage Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance	28	28	28	22
Total realized/unrealized gains (losses) included in Net income	(1)	1	(1)	0
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	0	(1)	0	(1)
Purchases and issuances	0	0	0	0
Sales and settlements	0	0	0	0
Transfer into Level 3	0	0	0	7
Transfer out of Level 3	0	0	0	0
Financial assets, Ending Balance	27	28	27	28
Asset-backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance	204	180	75	253
Total realized/unrealized gains (losses) included in Net income	0	0	3	3
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	(3)	0	(2)	(2)
Purchases and issuances	8	0	68	12
Sales and settlements	(7)	(4)	(23)	(49)
Transfer into Level 3	0	11	81	11
Transfer out of Level 3	(23)	(1)	(23)	(42)
Financial assets, Ending Balance	179	186	179	186
All other corporate [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance	313	295	335	236
Total realized/unrealized gains (losses) included in Net income	(1)	0	4	0
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	1	(4)	4	(14)
Purchases and issuances	51	6	72	61
Sales and settlements	(13)	(3)	(59)	(9)
Transfer into Level 3	91	0	91	24
Transfer out of Level 3	0	(4)	(5)	(8)
Financial assets, Ending Balance	442	290	442	290
Equity securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance	81	78	31	37
Total realized/unrealized gains (losses) included in Net income	0	(2)	1	(2)
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	(2)	0	2	2
Purchases and issuances	2	0	48	48
Sales and settlements	0	0	(9)	0
Transfer into Level 3	0	0	22	0
Transfer out of Level 3	0	(19)	(14)	(28)
Financial assets, Ending Balance	81	57	81	57
Assets of Managed Investment Entities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance	27	31	30	40
Total realized/unrealized gains (losses) included in Net income	0	0	(2)	(3)
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	0	0	0	0
Purchases and issuances	3	0	3	6
Sales and settlements	(1)	0	(2)	(6)
Transfer into Level 3	0	0	0	0
Transfer out of Level 3	0	0	0	(6)
Financial assets, Ending Balance	$ 29	$ 31	$ 29	$ 31