Fair Value Measurements (Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation
Beginning balance	$ 4	$ 5
Total gains or losses (realized/unrealized):
Included in net income	0	0
Included in other comprehensive income	0	0
Purchases	0	1
Sales	0	(1)
Transfers into Level 3	16	0
Transfers out of Level 3	0	(1)
Ending balance	20	4
Corporate Fixed Maturities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation
Beginning balance	2	3
Total gains or losses (realized/unrealized):
Included in net income	0	0
Included in other comprehensive income	0	0
Purchases	0	0
Sales	0	0
Transfers into Level 3	16	0
Transfers out of Level 3	0	(1)
Ending balance	18	2
States, Municipalities and Political Subdivisions Fixed Maturities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation
Beginning balance	0	1
Total gains or losses (realized/unrealized):
Included in net income	0	0
Included in other comprehensive income	0	0
Purchases	0	0
Sales	0	(1)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	0	0
Nonredeemable Preferred Equities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation
Beginning balance	2	1
Total gains or losses (realized/unrealized):
Included in net income	0	0
Included in other comprehensive income	0	0
Purchases	0	1
Sales	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	$ 2	$ 2