Fair Value (Quantitative Information) (Details)	Sep. 30, 2020	Dec. 31, 2019
Minimum | Interest rate contracts | Measurement Input, Swap Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	69	190
Minimum | Interest rate contracts | Measurement Input, Repurchase Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	(2)	(6)
Minimum | Foreign currency exchange rate contracts | Measurement Input, Swap Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	(34)	(22)
Minimum | Credit contracts | Measurement Input, Credit Spread
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	97	96
Minimum | Equity market contracts | Measurement Input, Price Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	0.27	0.14
Minimum | Equity market contracts | Measurement Input, Correlation
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	0.10	0.10
Minimum | Embedded derivatives direct and assumed guaranteed minimum benefits | Measurement Input, Utilization Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0	0
Minimum | Embedded derivatives direct and assumed guaranteed minimum benefits | Measurement Input, Withdrawal Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0025	0.0025
Minimum | Embedded derivatives direct and assumed guaranteed minimum benefits | Measurement Input, Long-Term Equity Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.1666	0.1624
Minimum | Embedded derivatives direct and assumed guaranteed minimum benefits | Measurement Input, Counterparty Credit Risk
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0004	0.0003
Minimum | Embedded derivatives direct and assumed guaranteed minimum benefits | Durations 1 - 10 | Measurement Input, Lapse Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0025	0.0025
Minimum | Embedded derivatives direct and assumed guaranteed minimum benefits | Durations 11 - 20 | Measurement Input, Lapse Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0470	0.03
Minimum | Embedded derivatives direct and assumed guaranteed minimum benefits | Durations 21 - 116 | Measurement Input, Lapse Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.02	0.02
Minimum | Embedded derivatives direct and assumed guaranteed minimum benefits | Ages 0 - 40 | Measurement Input, Mortality Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0001	0.0001
Minimum | Embedded derivatives direct and assumed guaranteed minimum benefits | Ages 41 - 60 | Measurement Input, Mortality Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0005	0.0004
Minimum | Embedded derivatives direct and assumed guaranteed minimum benefits | Ages 61 - 115 | Measurement Input, Mortality Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0031	0.0026
Minimum | U.S. corporate and foreign corporate | Valuation Technique, Matrix Pricing | Measurement Input, Offered Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	1	5
Minimum | U.S. corporate and foreign corporate | Valuation Technique, Market Approach | Measurement Input, Quoted Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	2	25
Minimum | RMBS | Valuation Technique, Market Approach | Measurement Input, Quoted Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	0	0
Minimum | ABS | Valuation Technique, Market Approach | Measurement Input, Quoted Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	5	8
Maximum | Interest rate contracts | Measurement Input, Swap Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	163	251
Maximum | Interest rate contracts | Measurement Input, Repurchase Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	7	6
Maximum | Foreign currency exchange rate contracts | Measurement Input, Swap Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	(14)	(5)
Maximum | Credit contracts | Measurement Input, Credit Spread
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	100	100
Maximum | Equity market contracts | Measurement Input, Price Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	0.31	0.23
Maximum | Equity market contracts | Measurement Input, Correlation
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	0.30	0.30
Maximum | Embedded derivatives direct and assumed guaranteed minimum benefits | Measurement Input, Utilization Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.22	0.22
Maximum | Embedded derivatives direct and assumed guaranteed minimum benefits | Measurement Input, Withdrawal Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.10	0.10
Maximum | Embedded derivatives direct and assumed guaranteed minimum benefits | Measurement Input, Long-Term Equity Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.2221	0.2165
Maximum | Embedded derivatives direct and assumed guaranteed minimum benefits | Measurement Input, Counterparty Credit Risk
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0045	0.0043
Maximum | Embedded derivatives direct and assumed guaranteed minimum benefits | Durations 1 - 10 | Measurement Input, Lapse Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	1	1
Maximum | Embedded derivatives direct and assumed guaranteed minimum benefits | Durations 11 - 20 | Measurement Input, Lapse Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	1	1
Maximum | Embedded derivatives direct and assumed guaranteed minimum benefits | Durations 21 - 116 | Measurement Input, Lapse Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	1	1
Maximum | Embedded derivatives direct and assumed guaranteed minimum benefits | Ages 0 - 40 | Measurement Input, Mortality Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0012	0.0018
Maximum | Embedded derivatives direct and assumed guaranteed minimum benefits | Ages 41 - 60 | Measurement Input, Mortality Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0065	0.0057
Maximum | Embedded derivatives direct and assumed guaranteed minimum benefits | Ages 61 - 115 | Measurement Input, Mortality Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	1	1
Maximum | U.S. corporate and foreign corporate | Valuation Technique, Matrix Pricing | Measurement Input, Offered Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	181	145
Maximum | U.S. corporate and foreign corporate | Valuation Technique, Market Approach | Measurement Input, Quoted Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	117	131
Maximum | RMBS | Valuation Technique, Market Approach | Measurement Input, Quoted Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	143	119
Maximum | ABS | Valuation Technique, Market Approach | Measurement Input, Quoted Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	106	101
Weighted Average | Interest rate contracts | Measurement Input, Swap Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	127
Weighted Average | Interest rate contracts | Measurement Input, Repurchase Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	3
Weighted Average | Foreign currency exchange rate contracts | Measurement Input, Swap Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	(19)
Weighted Average | Credit contracts | Measurement Input, Credit Spread
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	99
Weighted Average | Equity market contracts | Measurement Input, Price Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	0.30
Weighted Average | Equity market contracts | Measurement Input, Correlation
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	0.10
Weighted Average | Embedded derivatives direct and assumed guaranteed minimum benefits | Measurement Input, Utilization Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0017
Weighted Average | Embedded derivatives direct and assumed guaranteed minimum benefits | Measurement Input, Withdrawal Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0398
Weighted Average | Embedded derivatives direct and assumed guaranteed minimum benefits | Measurement Input, Long-Term Equity Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.1870
Weighted Average | Embedded derivatives direct and assumed guaranteed minimum benefits | Measurement Input, Counterparty Credit Risk
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0040
Weighted Average | Embedded derivatives direct and assumed guaranteed minimum benefits | Durations 1 - 10 | Measurement Input, Lapse Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0686
Weighted Average | Embedded derivatives direct and assumed guaranteed minimum benefits | Durations 11 - 20 | Measurement Input, Lapse Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0518
Weighted Average | Embedded derivatives direct and assumed guaranteed minimum benefits | Durations 21 - 116 | Measurement Input, Lapse Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0518
Weighted Average | Embedded derivatives direct and assumed guaranteed minimum benefits | Ages 0 - 40 | Measurement Input, Mortality Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0006
Weighted Average | Embedded derivatives direct and assumed guaranteed minimum benefits | Ages 41 - 60 | Measurement Input, Mortality Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0030
Weighted Average | Embedded derivatives direct and assumed guaranteed minimum benefits | Ages 61 - 115 | Measurement Input, Mortality Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0190
Weighted Average | U.S. corporate and foreign corporate | Valuation Technique, Matrix Pricing | Measurement Input, Offered Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	114	110
Weighted Average | U.S. corporate and foreign corporate | Valuation Technique, Market Approach | Measurement Input, Quoted Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	100	101
Weighted Average | RMBS | Valuation Technique, Market Approach | Measurement Input, Quoted Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	97	95
Weighted Average | ABS | Valuation Technique, Market Approach | Measurement Input, Quoted Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	98	98