Fair Value (Quantitative Information) (Details) - Fair Value, Inputs, Level 3 [Member]	Jun. 30, 2018 $ / shares	Dec. 31, 2017 $ / shares
Measurement Input, Age 0 - 40, Mortality Rate [Member] | Minimum
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.0000	0.0000
Measurement Input, Age 0 - 40, Mortality Rate [Member] | Maximum
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.0009	0.0009
Measurement Input, Age 41- 60, Mortality Rate [Member] | Minimum
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.0004	0.0004
Measurement Input, Age 41- 60, Mortality Rate [Member] | Maximum
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.0065	0.0065
Measurement Input, Age 61 - 115, Mortality Rate [Member] | Minimum
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.0026	0.0026
Measurement Input, Age 61 - 115, Mortality Rate [Member] | Maximum
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	1.0000	1.0000
Measurement Input, Duration 1 - 10, Lapse Rate [Member] | Minimum
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.0025	0.0025
Measurement Input, Duration 1 - 10, Lapse Rate [Member] | Maximum
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	1.0000	1.0000
Measurement Input, Duration 11 - 20, Lapse Rate [Member] | Minimum
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.02	0.02
Measurement Input, Duration 11 - 20, Lapse Rate [Member] | Maximum
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	1.00	1.00
Measurement Input, Duration 21 - 116, Lapse Rate [Member] | Minimum
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.02	0.02
Measurement Input, Duration 21 - 116, Lapse Rate [Member] | Maximum
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	1.00	1.00
Measurement Input, Utilization Rate [Member] | Minimum
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.0000	0.0000
Measurement Input, Utilization Rate [Member] | Maximum
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.2500	0.2500
Measurement Input, Withdrawal Rate [Member] | Minimum
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.0025	0.0025
Measurement Input, Withdrawal Rate [Member] | Maximum
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.1000	0.1000
Measurement Input, Long Term Equity Volatilities [Member] | Minimum
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.1740	0.1740
Measurement Input, Long Term Equity Volatilities [Member] | Maximum
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.2500	0.2500
Measurement Input, Entity Credit Risk [Member] | Minimum
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.0112	0.0064
Measurement Input, Entity Credit Risk [Member] | Maximum
Fair Value, Option, Quantitative Disclosures [Line Items]
Embedded Derivative Liability, Measurement Input	0.0206	0.0143
U.S. and foreign corporate | Measurement Input, Offered Price [Member] | Minimum | Valuation Technique, Matrix Pricing [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Securities, Available-for-sale, Measurement Input	87	93
U.S. and foreign corporate | Measurement Input, Offered Price [Member] | Maximum | Valuation Technique, Matrix Pricing [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Securities, Available-for-sale, Measurement Input	137	142
U.S. and foreign corporate | Measurement Input, Offered Price [Member] | Weighted Average | Valuation Technique, Matrix Pricing [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Securities, Available-for-sale, Measurement Input	106	110
U.S. and foreign corporate | Measurement Input, Quoted Price [Member] | Minimum | Market Approach Valuation Technique
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Securities, Available-for-sale, Measurement Input	53	0
U.S. and foreign corporate | Measurement Input, Quoted Price [Member] | Maximum | Market Approach Valuation Technique
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Securities, Available-for-sale, Measurement Input	353	443
U.S. and foreign corporate | Measurement Input, Quoted Price [Member] | Weighted Average | Market Approach Valuation Technique
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Securities, Available-for-sale, Measurement Input	105	76
Residential Mortgage Backed Securities [Member] | Measurement Input, Quoted Price [Member] | Minimum | Market Approach Valuation Technique
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Securities, Available-for-sale, Measurement Input	56	3
Residential Mortgage Backed Securities [Member] | Measurement Input, Quoted Price [Member] | Maximum | Market Approach Valuation Technique
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Securities, Available-for-sale, Measurement Input	107	107
Residential Mortgage Backed Securities [Member] | Measurement Input, Quoted Price [Member] | Weighted Average | Market Approach Valuation Technique
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Securities, Available-for-sale, Measurement Input	95	94
Asset-backed Securities [Member] | Measurement Input, Offered Price [Member] | Minimum | Valuation Technique, Consensus Pricing Model [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Securities, Available-for-sale, Measurement Input		100
Asset-backed Securities [Member] | Measurement Input, Offered Price [Member] | Maximum | Valuation Technique, Consensus Pricing Model [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Securities, Available-for-sale, Measurement Input		100
Asset-backed Securities [Member] | Measurement Input, Offered Price [Member] | Weighted Average | Valuation Technique, Consensus Pricing Model [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Securities, Available-for-sale, Measurement Input		100
Asset-backed Securities [Member] | Measurement Input, Quoted Price [Member] | Minimum | Market Approach Valuation Technique
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Securities, Available-for-sale, Measurement Input	100	100
Asset-backed Securities [Member] | Measurement Input, Quoted Price [Member] | Maximum | Market Approach Valuation Technique
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Securities, Available-for-sale, Measurement Input	102	104
Asset-backed Securities [Member] | Measurement Input, Quoted Price [Member] | Weighted Average | Market Approach Valuation Technique
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt Securities, Available-for-sale, Measurement Input	100	101
Credit Risk Contract [Member] | Measurement Input, Credit Spread [Member] | Minimum | Income Approach Valuation Technique
Fair Value, Option, Quantitative Disclosures [Line Items]
Derivative Asset (Liability) Net, Measurement Input	97.00	0.00
Credit Risk Contract [Member] | Measurement Input, Credit Spread [Member] | Maximum | Income Approach Valuation Technique
Fair Value, Option, Quantitative Disclosures [Line Items]
Derivative Asset (Liability) Net, Measurement Input	99.00	0.00
Equity Contract [Member] | Measurement Input, Option Volatility [Member] | Minimum | Income Approach Valuation Technique
Fair Value, Option, Quantitative Disclosures [Line Items]
Derivative Asset (Liability) Net, Measurement Input	0.17	0.11
Equity Contract [Member] | Measurement Input, Option Volatility [Member] | Maximum | Income Approach Valuation Technique
Fair Value, Option, Quantitative Disclosures [Line Items]
Derivative Asset (Liability) Net, Measurement Input	0.30	0.31
Equity Contract [Member] | Measurement Input, Comparability Adjustment [Member] | Minimum | Income Approach Valuation Technique
Fair Value, Option, Quantitative Disclosures [Line Items]
Derivative Asset (Liability) Net, Measurement Input	0.10	0.10
Equity Contract [Member] | Measurement Input, Comparability Adjustment [Member] | Maximum | Income Approach Valuation Technique
Fair Value, Option, Quantitative Disclosures [Line Items]
Derivative Asset (Liability) Net, Measurement Input	0.30	0.30