Segment Information (Reconciliation Of Revenue From Segments To Consolidated) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Total revenues	$ 4,264	$ 3,511	$ 11,893	$ 10,588
Annuities Segment [Member]
Segment Reporting Information [Line Items]
Total revenues	1,118	1,073	3,297	3,211
Retirement Plan Services Segment [Member]
Segment Reporting Information [Line Items]
Total revenues	294	291	878	863
Life Insurance Segment [Member]
Segment Reporting Information [Line Items]
Total revenues	1,766	1,614	5,106	4,874
Group Protection Segment [Member]
Segment Reporting Information [Line Items]
Total revenues	1,128	564	2,618	1,646
Other Operations [Member]
Segment Reporting Information [Line Items]
Total revenues	56	65	182	220
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Excluded realized gain (loss), pre-tax	$ (98)	(97)	$ (188)	(229)
Amortization of deferred gain arising from reserve changes on business sold through reinsurance, pre-tax				1
Amortization of DFEL associated with benefit ratio unlocking, pre-tax		$ 1		$ 2