Segment Information (Schedule Of Disaggregation Of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 334	$ 646
Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	22	43
Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	312	603
Fee Income [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	181	361
Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	153	285
Annuities Segment [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	252	505
Annuities Segment [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	18	36
Annuities Segment [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	234	469
Annuities Segment [Member] | Fee Income [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	133	266
Annuities Segment [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	119	239
Retirement Plan Services Segment [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	47	93
Retirement Plan Services Segment [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	2	3
Retirement Plan Services Segment [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	45	90
Retirement Plan Services Segment [Member] | Fee Income [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	42	84
Retirement Plan Services Segment [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	5	9
Life Insurance Segment [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	8	16
Life Insurance Segment [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	2	4
Life Insurance Segment [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	6	12
Life Insurance Segment [Member] | Fee Income [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	6	11
Life Insurance Segment [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	2	5
Group Protection Segment [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	27	32
Group Protection Segment [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	27	32
Group Protection Segment [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 27	$ 32