Contingencies And Commitments (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Loss Contingencies [Line Items]
Total rental expense on operating leases	$ 43	$ 36	$ 37
Sale-leaseback transactions, net	88	62
Total accumulated amortization related to sales leaseback transaction	282	101
Loss contingency accrual, insurance-related assessment, premium tax offset	$ (18)	$ (17)
Variable Annuity Product Concentration Risk [Member] \| Variable Annuity Deposits Total [Member]
Loss Contingencies [Line Items]
Concentration risk, percentage	11.00%	14.00%	21.00%
Variable Annuity Product Concentration Risk [Member] \| Variable Annuity Account Values Total [Member]
Loss Contingencies [Line Items]
Concentration risk, percentage	38.00%	40.00%	41.00%
Fund Choice Concentration Risk [Member] \| Variable Annuity Deposits Total [Member]
Loss Contingencies [Line Items]
Concentration risk, percentage	16.00%	20.00%	23.00%
Fund Choice Concentration Risk [Member] \| Variable Annuity Account Values Total [Member]
Loss Contingencies [Line Items]
Concentration risk, percentage	45.00%	47.00%	47.00%
Maximum [Member] \| Pending Litigation [Member]
Loss Contingencies [Line Items]
Loss contingency, estimate	$ 50

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Amount of rent expense incurred for leased assets, including but not limited to, furniture and equipment, that is not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

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The amount of insurance-related assessment liability that is expected to be recovered through a premium tax offset based on current laws applied to in-force policies.

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Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

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The accumulated depreciation and amortization related to the asset(s) sold in connection with the property sold to another party and leased back to the seller.

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