Fair Value (Quantitative Information) (Details) - $ / shares	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Interest rate contracts \| Minimum \| Income Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Swap yield	0.00%	3.17%
Interest rate contracts \| Maximum \| Income Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Swap yield	0.00%	3.17%
Credit contracts \| Minimum \| Income Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Credit spreads	0.97%	0.00%
Credit contracts \| Maximum \| Income Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Credit spreads	0.98%	0.00%
Equity market contracts \| Minimum \| Income Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Correlation	40.00%	70.00%
Volatility	14.00%	17.00%
Equity market contracts \| Maximum \| Income Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Correlation	40.00%	70.00%
Volatility	32.00%	36.00%
Embedded derivatives direct and ceded guaranteed minimum benefits \| Minimum \| Income Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Utilization rates	0.00%	0.00%
Withdrawal rates	0.25%	0.25%
Long-term equity volatilities	17.40%	17.40%
Nonperformance risk spread	0.04%	0.04%
Embedded derivatives direct and ceded guaranteed minimum benefits \| Minimum \| Income Approach Valuation Technique \| Durations 1 - 10
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Lapse Rate	0.25%	0.25%
Embedded derivatives direct and ceded guaranteed minimum benefits \| Minimum \| Income Approach Valuation Technique \| Durations 11 - 20
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Lapse Rate	2.00%	3.00%
Embedded derivatives direct and ceded guaranteed minimum benefits \| Minimum \| Income Approach Valuation Technique \| Durations 21 - 116
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Lapse Rate	2.00%	3.00%
Embedded derivatives direct and ceded guaranteed minimum benefits \| Minimum \| Income Approach Valuation Technique \| Ages 0 - 40
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Mortality Rate	0.00%	0.00%
Embedded derivatives direct and ceded guaranteed minimum benefits \| Minimum \| Income Approach Valuation Technique \| Ages 41 - 60
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Mortality Rate	0.04%	0.04%
Embedded derivatives direct and ceded guaranteed minimum benefits \| Minimum \| Income Approach Valuation Technique \| Ages 61 – 115
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Mortality Rate	0.26%	0.26%
Embedded derivatives direct and ceded guaranteed minimum benefits \| Maximum \| Income Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Utilization rates	25.00%	25.00%
Withdrawal rates	10.00%	10.00%
Long-term equity volatilities	25.00%	25.00%
Nonperformance risk spread	0.57%	0.52%
Embedded derivatives direct and ceded guaranteed minimum benefits \| Maximum \| Income Approach Valuation Technique \| Durations 1 - 10
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Lapse Rate	100.00%	100.00%
Embedded derivatives direct and ceded guaranteed minimum benefits \| Maximum \| Income Approach Valuation Technique \| Durations 11 - 20
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Lapse Rate	100.00%	100.00%
Embedded derivatives direct and ceded guaranteed minimum benefits \| Maximum \| Income Approach Valuation Technique \| Durations 21 - 116
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Lapse Rate	100.00%	100.00%
Embedded derivatives direct and ceded guaranteed minimum benefits \| Maximum \| Income Approach Valuation Technique \| Ages 0 - 40
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Mortality Rate	0.09%	0.09%
Embedded derivatives direct and ceded guaranteed minimum benefits \| Maximum \| Income Approach Valuation Technique \| Ages 41 - 60
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Mortality Rate	0.65%	0.65%
Embedded derivatives direct and ceded guaranteed minimum benefits \| Maximum \| Income Approach Valuation Technique \| Ages 61 – 115
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Mortality Rate	100.00%	100.00%
U.S. corporate and foreign corporate \| Minimum \| Market Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Delta spread adjustments	0.00%	(0.65%)
Fair Value Inputs, Offered Quotes Matrix Pricing	$ 18	$ 96
Offered quotes	68	68
Quoted prices	$ 13	$ 13
U.S. corporate and foreign corporate \| Maximum \| Market Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Delta spread adjustments	0.00%	2.40%
Fair Value Inputs, Offered Quotes Matrix Pricing	$ 138	$ 96
Offered quotes	109	95
Quoted prices	$ 700	$ 780
U.S. corporate and foreign corporate \| Weighted Average \| Market Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Delta spread adjustments	0.00%	0.49%
Fair Value Inputs, Offered Quotes Matrix Pricing	$ 104	$ 96
Offered quotes	86	80
Quoted prices	99	314
RMBS \| Minimum \| Market Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Offered quotes	38	29
RMBS \| Maximum \| Market Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Offered quotes	111	292
RMBS \| Weighted Average \| Market Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Offered quotes	91	93
ABS \| Minimum \| Market Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Offered quotes	98	66
Quoted prices	94	97
ABS \| Maximum \| Market Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Offered quotes	100	105
Quoted prices	106	103
ABS \| Weighted Average \| Market Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Offered quotes	99	99
Quoted prices	$ 100	$ 100

Correlation.

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Fair value inputs long-term equity volatilities.

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Matrix Pricing - Price at which a dealer is willing to buy an instrument, used as an input to measure fair value.

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Quoted prices

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- Definition

Swap Yield

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- Definition

Fair value inputs utilization rates.

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- Definition

Fair value inputs withdrawal rates.

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- Definition

Measure of dispersion, in percentage terms (for instance, the standard deviation or variance), for a given stock price.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Percentage of adjustment to the observed price for a similar asset or liability when an identical transaction does not exist, used as an input to measure fair value.

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- Definition

Risk that one party to the contract will default expressed as a percentage, used as an input to measure fair value.

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Risk associated with risk of default, credit spread risk and downgrade risk, expressed as a percentage, used as an input to measure fair value.

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- Definition

Price at which a dealer is willing to buy an instrument, used as an input to measure fair value.

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- Definition

Anticipated rate of future terminations of contracts in force as of the balance sheet date, which is included in determining the amount of the specified guaranteed benefit obligation as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 20
-Section 55
-Paragraph 15
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=6588021&loc=d3e7104-158389

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
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-Section 50
-Paragraph 6
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Actuarially determined death rate of policyholders, which is included in determining the amount of the specified guaranteed benefit obligation as of the balance sheet date.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 20
-Section 55
-Paragraph 15
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