Segment Information (Reconciliation Of Revenue From Segments To Consolidated) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Total revenues	$ 4,135	$ 5,361	$ 3,517	$ 4,425	$ 4,344	$ 4,638	$ 4,310	$ 3,965	$ 17,439	$ 17,258	$ 16,424
Annuities Segment [Member]
Segment Reporting Information [Line Items]
Total revenues									4,455	4,600	4,383
Retirement Plan Services Segment [Member]
Segment Reporting Information [Line Items]
Total revenues									1,213	1,200	1,178
Life Insurance Segment [Member]
Segment Reporting Information [Line Items]
Total revenues									7,516	7,438	6,922
Group Protection Segment [Member]
Segment Reporting Information [Line Items]
Total revenues									4,793	4,588	3,757
Other Operations [Member]
Segment Reporting Information [Line Items]
Total revenues									185	220	235
Excluded Realized Gain (Loss), Pre-Tax [Member]
Segment Reporting Information [Line Items]
Total revenues									(721)	(794)	(46)
Amortization Of DFEL Associated With Benefit Ratio Unlocking, Pre-Tax [Member]
Segment Reporting Information [Line Items]
Total revenues									$ (2)	$ 6	$ (5)