Segment Information (Reconciliation Of Income (Loss) From Operations By Segment To Consolidated Net Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Net income (loss)	$ 363	$ 385	$ 616	$ 752
Segment Reconciling Items [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Excluded realized gain (loss), after-tax	(128)	(41)	(443)	(69)
Gain (loss) on early extinguishment of debt, after-tax				(19)
Benefit ratio unlocking, after-tax	46	7	188	(3)
Net impact from the Tax Cuts and Jobs Act				(13)
Acquisition and integration costs related to mergers and acquisitions, after tax	(33)	(35)	(48)	(39)
Annuities Segment [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Net income (loss)	266	275	517	542
Retirement Plan Services Segment [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Net income (loss)	42	43	81	86
Life Insurance Segment [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Net income (loss)	168	150	325	294
Group Protection Segment [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Net income (loss)	68	45	123	74
Other Operations [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Net income (loss)	$ (66)	$ (59)	$ (127)	$ (101)

Benefit ratio unlocking

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Excluded realized gain (loss), after-tax

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This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

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Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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