Fair Value Measurements (Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation
Beginning balance	$ 20	$ 4
Total gains or losses (realized/unrealized):
Included in net income	0	0
Included in other comprehensive income	1	0
Purchases	37	0
Sales	0	0
Transfers into Level 3	0	16
Transfers out of Level 3	(3)	0
Ending balance	55	20
Corporate Fixed Maturities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation
Beginning balance	18	2
Total gains or losses (realized/unrealized):
Included in net income	0	0
Included in other comprehensive income	0	0
Purchases	36	0
Sales	0	0
Transfers into Level 3	0	16
Transfers out of Level 3	(3)	0
Ending balance	51	18
Taxable Fixed Maturities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation
Beginning balance	0	0
Total gains or losses (realized/unrealized):
Included in net income	0	0
Included in other comprehensive income	0	0
Purchases	1	0
Sales	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	1	0
Nonredeemable Preferred Equities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation
Beginning balance	2	2
Total gains or losses (realized/unrealized):
Included in net income	0	0
Included in other comprehensive income	1	0
Purchases	0	0
Sales	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	$ 3	$ 2