Segment Information (Reconciliation Of Income (Loss) From Operations By Segment To Consolidated Net Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Net income (loss)	$ 502	$ 133
Annuities Segment [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Net income (loss)	322	239
Retirement Plan Services Segment [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Net income (loss)	37	37
Life Insurance Segment [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Net income (loss)	190	159
Group Protection Segment [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Net income (loss)	40	55
Other Operations [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Net income (loss)	(33)	(33)
Segment Reconciling Items [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Excluded realized gain (loss), after-tax	(44)	(309)
Acquisition and integration costs related to mergers and acquisitions, after-tax	$ (5)	$ (15)