Segment Information (Reconciliation Of Income (Loss) From Operations By Segment To Consolidated Net Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Gain (loss) on early extinguishment of debt, after-tax			$ (15)
Net income (loss)	$ (94)	$ 363	(42)	$ 616
Segment Reconciling Items [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Excluded realized gain (loss), after-tax	(548)	(128)	(609)	(443)
Gain (loss) on early extinguishment of debt, after-tax	(12)		(12)
Benefit ratio unlocking, after-tax	282	46	(67)	188
Acquisition and integration costs related to mergers and acquisitions, after tax	(3)	(33)	(6)	(48)
Annuities Segment [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Net income (loss)	237	266	498	517
Retirement Plan Services Segment [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Net income (loss)	30	42	69	81
Life Insurance Segment [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Net income (loss)	(37)	168	134	325
Group Protection Segment [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Net income (loss)	39	68	79	123
Other Operations [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Net income (loss)	$ (82)	$ (66)	$ (128)	$ (127)