Fair Value (Quantitative Information) (Details)	Sep. 30, 2021	Dec. 31, 2020
Minimum | Interest rate contracts | Measurement Input, Swap Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	149	92
Minimum | Interest rate contracts | Measurement Input, Repurchase Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	0	(12)
Minimum | Interest rate contracts | Measurement Input, Price Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	0	0
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	(129)	(309)
Minimum | Credit contracts | Measurement Input, Credit Spread
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	96	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	0.21
Minimum | Equity market contracts | Measurement Input, Correlation
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	0	0.10
Minimum | Embedded derivatives direct, assumed and ceded guaranteed minimum benefits | Mortality rates: Ages 0 - 40
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0	0
Minimum | Embedded derivatives direct, assumed and ceded guaranteed minimum benefits | Mortality rates: Ages 41 - 60
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0003	0.0003
Minimum | Embedded derivatives direct, assumed and ceded guaranteed minimum benefits | Mortality rates: Ages 61 - 115
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0012	0.0012
Minimum | Embedded derivatives direct, assumed and ceded guaranteed minimum benefits | Lapse rates: Durations 1 - 10
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0025	0.0025
Minimum | Embedded derivatives direct, assumed and ceded guaranteed minimum benefits | Lapse rates: Durations 11 - 20
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0050	0.0050
Minimum | Embedded derivatives direct, assumed and ceded guaranteed minimum benefits | Lapse rates: Durations 21 - 116
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0050	0.0050
Minimum | Embedded derivatives direct, assumed and ceded 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, assumed and ceded guaranteed minimum benefits | Measurement Input, Withdrawal Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0	0
Minimum | Embedded derivatives direct, assumed and ceded 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	0.0771	0.0833
Minimum | Embedded derivatives direct, assumed and ceded guaranteed minimum benefits | Measurement Input, Counterparty Credit Risk
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0005	0.0004
Minimum | U.S. corporate and foreign corporate securities [Member] | 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	0
Minimum | U.S. corporate and foreign corporate securities [Member] | 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 | U.S. corporate and foreign corporate securities [Member] | Valuation Technique, Consensus Pricing Model | Measurement Input, Offered Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	99	54
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	3	1
Minimum | ABS | Valuation Technique, Consensus Pricing Model | Measurement Input, Offered Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	102	100
Maximum | Interest rate contracts | Measurement Input, Swap Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	221	184
Maximum | Interest rate contracts | Measurement Input, Repurchase Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	0	1
Maximum | Interest rate contracts | Measurement Input, Price Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	0.01	0
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	1,873	248
Maximum | Credit contracts | Measurement Input, Credit Spread
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	128	99
Maximum | Equity market contracts | Measurement Input, Price Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	0	0.29
Maximum | Equity market contracts | Measurement Input, Correlation
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	0	0.30
Maximum | Embedded derivatives direct, assumed and ceded guaranteed minimum benefits | Mortality rates: Ages 0 - 40
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0017	0.0017
Maximum | Embedded derivatives direct, assumed and ceded guaranteed minimum benefits | Mortality rates: Ages 41 - 60
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0075	0.0075
Maximum | Embedded derivatives direct, assumed and ceded guaranteed minimum benefits | Mortality rates: Ages 61 - 115
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	1	1
Maximum | Embedded derivatives direct, assumed and ceded guaranteed minimum benefits | Lapse rates: Durations 1 - 10
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	1	1
Maximum | Embedded derivatives direct, assumed and ceded guaranteed minimum benefits | Lapse rates: Durations 11 - 20
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	1	1
Maximum | Embedded derivatives direct, assumed and ceded guaranteed minimum benefits | Lapse rates: Durations 21 - 116
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	1	1
Maximum | Embedded derivatives direct, assumed and ceded 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, assumed and ceded guaranteed minimum benefits | Measurement Input, Withdrawal Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.20	0.20
Maximum | Embedded derivatives direct, assumed and ceded 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	0.25	0.27
Maximum | Embedded derivatives direct, assumed and ceded guaranteed minimum benefits | Measurement Input, Counterparty Credit Risk
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0117	0.0118
Maximum | U.S. corporate and foreign corporate securities [Member] | Valuation Technique, Matrix Pricing | Measurement Input, Offered Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	170	186
Maximum | U.S. corporate and foreign corporate securities [Member] | Valuation Technique, Market Approach | Measurement Input, Quoted Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	113	116
Maximum | U.S. corporate and foreign corporate securities [Member] | Valuation Technique, Consensus Pricing Model | Measurement Input, Offered Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	107	104
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	180	159
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	109	112
Maximum | ABS | Valuation Technique, Consensus Pricing Model | Measurement Input, Offered Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	102	100
Weighted Average | Interest rate contracts | Measurement Input, Swap Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	199	149
Weighted Average | Interest rate contracts | Measurement Input, Repurchase Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	0	(6)
Weighted Average | Interest rate contracts | Measurement Input, Price Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	0.01	0
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	117	(144)
Weighted Average | Credit contracts | Measurement Input, Credit Spread
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	104	98
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	0.28
Weighted Average | Equity market contracts | Measurement Input, Correlation
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Asset (Liability) Net, Measurement Input	0	0.10
Weighted Average | Embedded derivatives direct, assumed and ceded guaranteed minimum benefits | Mortality rates: Ages 0 - 40
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0008	0.0006
Weighted Average | Embedded derivatives direct, assumed and ceded guaranteed minimum benefits | Mortality rates: Ages 41 - 60
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0027	0.0030
Weighted Average | Embedded derivatives direct, assumed and ceded guaranteed minimum benefits | Mortality rates: Ages 61 - 115
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0208	0.0190
Weighted Average | Embedded derivatives direct, assumed and ceded guaranteed minimum benefits | Lapse rates: Durations 1 - 10
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0630	0.0686
Weighted Average | Embedded derivatives direct, assumed and ceded guaranteed minimum benefits | Lapse rates: Durations 11 - 20
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0522	0.0518
Weighted Average | Embedded derivatives direct, assumed and ceded guaranteed minimum benefits | Lapse rates: Durations 21 - 116
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0522	0.0518
Weighted Average | Embedded derivatives direct, assumed and ceded guaranteed minimum benefits | Measurement Input, Utilization Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0022	0.0017
Weighted Average | Embedded derivatives direct, assumed and ceded guaranteed minimum benefits | Measurement Input, Withdrawal Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0372	0.0398
Weighted Average | Embedded derivatives direct, assumed and ceded 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	0.1860	0.1870
Weighted Average | Embedded derivatives direct, assumed and ceded guaranteed minimum benefits | Measurement Input, Counterparty Credit Risk
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded Derivative Asset (Liability) Net, Measurement Input	0.0035	0.0040
Weighted Average | U.S. corporate and foreign corporate securities [Member] | Valuation Technique, Matrix Pricing | Measurement Input, Offered Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	111	117
Weighted Average | U.S. corporate and foreign corporate securities [Member] | Valuation Technique, Market Approach | Measurement Input, Quoted Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	99	98
Weighted Average | U.S. corporate and foreign corporate securities [Member] | Valuation Technique, Consensus Pricing Model | Measurement Input, Offered 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	99	98
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	102	100
Weighted Average | ABS | Valuation Technique, Consensus Pricing Model | Measurement Input, Offered Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	102	100