Derivative Instruments (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	$ 6.0
Maximum Length of Time Hedged in Cash Flow Hedge	39 years
Credit Derivative, Maximum Exposure, Undiscounted	$ 2.0	$ 3.0
Credit Risk Derivatives, at Fair Value, Net Asset (Liability) (less than)	(0.1)	(0.3)
Future Policy Benefits
Embedded Derivative, Fair Value of Embedded Derivative, Net	(5,453.0)	(5,041.0)
Reinsurance Recoverables
Embedded Derivative, Fair Value of Embedded Derivative, Net	5,458.0	5,474.0
Reinsurance Recoverables \| PALAC and Prudential Insurance
Embedded Derivative, Fair Value of Embedded Derivative, Net	5,445.0	5,041.0
Reinsurance Recoverables \| Union Hamilton Reinsurance, Ltd.
Embedded Derivative, Fair Value of Embedded Derivative, Net	13.0	0.0
Reinsurance Recoverables \| UPARC
Embedded Derivative, Fair Value of Embedded Derivative, Net		433.0
Policyholders' Account Balances
Embedded Derivative, Fair Value of Embedded Derivative, Net	$ (47.0)	$ (20.0)

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994

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Maximum potential amount of future undiscounted payments that could be required under the credit derivative, before reduction for potential recoveries under recourse or collateralization provisions.

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Fair value of credit risk derivative asset after deduction of credit risk derivative liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4K
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5708775-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13495-108611

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Net fair value as of the balance sheet date of the embedded derivative or group of embedded derivatives classified as assets, net of those classified as liabilities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

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Maximum length of time over which the entity is hedging its exposure to the variability in future cash flows for forecasted transactions, excluding those forecasted transactions related to the payment of variable interest on existing financial instruments, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 30
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