Segment Information (Reconciliation Of Income (Loss) From Operations By Segment To Consolidated Net Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Impairment											$ (905)
Net income (loss)	$ 460	$ (201)	$ 222	$ 133	$ 368	$ 378	$ 420	$ 407	614	1,573	2,018
Annuities Segment [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Impairment
Net income (loss)									987	1,122	1,072
Retirement Plan Services Segment [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Impairment
Net income (loss)									162	160	142
Life Insurance Segment [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Impairment
Net income (loss)									267	530	522
Group Protection Segment [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Impairment
Net income (loss)									237	186	103
Other Operations [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Net income (loss)									(148)	(130)	(30)
Segment Reconciling Items [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Excluded realized gain (loss), after-tax									(804)	(225)	(409)
(Gain) loss on early extinguishment of debt, after tax											(3)
Net impact from the Tax Cuts and Jobs Act									16	(3)	1,526
Impairment											$ (905)
Acquisition and integration costs related to mergers and acquisitions, after-tax									$ (103)	$ (67)