Segment Information (Schedule Of Disaggregation Of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 353	$ 999
Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	21	62
Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	332	937
Fee Income [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	185	546
Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	168	453
Annuities Segment [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	257	762
Annuities Segment [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	17	53
Annuities Segment [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	240	709
Annuities Segment [Member] | Fee Income [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	137	403
Annuities Segment [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	120	359
Retirement Plan Services Segment [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	47	140
Retirement Plan Services Segment [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1	3
Retirement Plan Services Segment [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	46	137
Retirement Plan Services Segment [Member] | Fee Income [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	42	126
Retirement Plan Services Segment [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	5	14
Life Insurance Segment [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	8	24
Life Insurance Segment [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3	6
Life Insurance Segment [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	5	18
Life Insurance Segment [Member] | Fee Income [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	6	17
Life Insurance Segment [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	2	7
Group Protection Segment [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	41	73
Group Protection Segment [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	41	73
Group Protection Segment [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 41	$ 73