Segment Information (Reconciliation of Federal Income Tax Expense (Benefit) From Segments to Consolidated) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Federal Income Tax Expense (Benefit) from Segments to Consolidated [Abstract]
Income tax expense (benefit)	$ (37)	$ 257	$ (1,287)
Annuities Segment [Member]
Reconciliation of Federal Income Tax Expense (Benefit) from Segments to Consolidated [Abstract]
Income tax expense (benefit)	148	187	198
Retirement Plan Services Segment [Member]
Reconciliation of Federal Income Tax Expense (Benefit) from Segments to Consolidated [Abstract]
Income tax expense (benefit)	21	28	50
Life Insurance Segment [Member]
Reconciliation of Federal Income Tax Expense (Benefit) from Segments to Consolidated [Abstract]
Income tax expense (benefit)	50	116	236
Group Protection Segment [Member]
Reconciliation of Federal Income Tax Expense (Benefit) from Segments to Consolidated [Abstract]
Income tax expense (benefit)	63	50	55
Other Operations [Member]
Reconciliation of Federal Income Tax Expense (Benefit) from Segments to Consolidated [Abstract]
Income tax expense (benefit)	(61)	(48)	(78)
Excluded Realized Gain (Loss) [Member]
Reconciliation of Federal Income Tax Expense (Benefit) from Segments to Consolidated [Abstract]
Income tax expense (benefit)	(215)	(61)	(220)
Gain (loss) on early extinguishment of debt [Member]
Reconciliation of Federal Income Tax Expense (Benefit) from Segments to Consolidated [Abstract]
Income tax expense (benefit)			(2)
Net Impact From Tax Cuts And Jobs Act [Member]
Reconciliation of Federal Income Tax Expense (Benefit) from Segments to Consolidated [Abstract]
Income tax expense (benefit)	(16)	3	$ (1,526)
Acquisition And Integration Costs Related To Mergers And Acquisitions [Member]
Reconciliation of Federal Income Tax Expense (Benefit) from Segments to Consolidated [Abstract]
Income tax expense (benefit)	$ (27)	$ (18)