Segment Information (Reconciliation Of Revenue From Segments To Consolidated) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule Of Segment Reporting And Reconcilliation [Line Items]
Total revenues	$ 3,685	$ 3,411	$ 3,282	$ 3,176	$ 3,122	$ 3,009	$ 2,999	$ 2,839	$ 13,554	$ 11,969	$ 11,535
Annuities [Member]
Schedule Of Segment Reporting And Reconcilliation [Line Items]
Total revenues									3,746	3,321	2,975
Retirement Plan Services [Member]
Schedule Of Segment Reporting And Reconcilliation [Line Items]
Total revenues									1,090	1,071	1,024
Life Insurance [Member]
Schedule Of Segment Reporting And Reconcilliation [Line Items]
Total revenues									6,003	5,170	5,056
Group Protection [Member]
Schedule Of Segment Reporting And Reconcilliation [Line Items]
Total revenues									2,445	2,260	2,091
Other Operations [Member]
Schedule Of Segment Reporting And Reconcilliation [Line Items]
Total revenues									432	417	423
Excluded realized gain (loss) pre-tax [Member]
Schedule Of Segment Reporting And Reconcilliation [Line Items]
Total revenues									(165)	(274)	(39)
Amortization of deferred gain arising from reserve changes on business sold through reinsurance, pre-tax [Member]
Schedule Of Segment Reporting And Reconcilliation [Line Items]
Total revenues									3	3	4
Amortization Of DFEL associated with benefit ratio unlocking, pre-tax [Member]
Schedule Of Segment Reporting And Reconcilliation [Line Items]
Total revenues										1	1
Parent Company [Member]
Schedule Of Segment Reporting And Reconcilliation [Line Items]
Total revenues									$ 918	$ 849	$ 783