Fair Values of Assets and Liabilities (Unobservable inputs) (Details) $ in Millions		Jun. 30, 2020 USD ($)		Dec. 31, 2019 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fixed maturities, fair value		$ 21,587		$ 20,902
Corporate debt securities (private placements) [Member] | Discounted cash flow [Member] | Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fixed maturities, fair value		$ 730		$ 735
Corporate debt securities (private placements) [Member] | Minimum [Member] | Discounted cash flow [Member] | Level 3 [Member] | Yield/spread to U.S. Treasuries [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fixed maturities, measurement inputs		0.014		0.008
Corporate debt securities (private placements) [Member] | Maximum [Member] | Discounted cash flow [Member] | Level 3 [Member] | Yield/spread to U.S. Treasuries [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fixed maturities, measurement inputs		0.053		0.028
Corporate debt securities (private placements) [Member] | Weighted average [Member] | Discounted cash flow [Member] | Level 3 [Member] | Yield/spread to U.S. Treasuries [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fixed maturities, measurement inputs		0.022	[1]	0.013
Asset backed securities [Member] | Discounted cash flow [Member] | Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fixed maturities, fair value		$ 352		$ 389
Asset backed securities [Member] | Discounted cash flow [Member] | Level 3 [Member] | Annual default rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fixed maturities, measurement inputs		0.043		0.035
Asset backed securities [Member] | Discounted cash flow [Member] | Level 3 [Member] | Loss severity [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fixed maturities, measurement inputs		0.250		0.250
Asset backed securities [Member] | Minimum [Member] | Discounted cash flow [Member] | Level 3 [Member] | Yield/spread to swap rates [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fixed maturities, measurement inputs		7.50		1.20
Asset backed securities [Member] | Maximum [Member] | Discounted cash flow [Member] | Level 3 [Member] | Yield/spread to swap rates [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fixed maturities, measurement inputs		10		1.70
Asset backed securities [Member] | Weighted average [Member] | Discounted cash flow [Member] | Level 3 [Member] | Annual default rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fixed maturities, measurement inputs		0.043
Asset backed securities [Member] | Weighted average [Member] | Discounted cash flow [Member] | Level 3 [Member] | Loss severity [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fixed maturities, measurement inputs		0.250
Asset backed securities [Member] | Weighted average [Member] | Discounted cash flow [Member] | Level 3 [Member] | Yield/spread to swap rates [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fixed maturities, measurement inputs		7.64	[2]	1.23
IUL embedded derivatives [Member] | Discounted cash flow [Member] | Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, fair value		$ 882		$ 881
IUL embedded derivatives [Member] | Discounted cash flow [Member] | Level 3 [Member] | Nonperformance risk [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, measurement inputs	[3]	0.95		0.65
IUL embedded derivatives [Member] | Weighted average [Member] | Discounted cash flow [Member] | Level 3 [Member] | Nonperformance risk [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, measurement inputs	[3]	0.95
Fixed deferred indexed annuity embedded derivatives [Member] | Discounted cash flow [Member] | Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, fair value		$ 41		$ 43
Fixed deferred indexed annuity embedded derivatives [Member] | Discounted cash flow [Member] | Level 3 [Member] | Nonperformance risk [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, measurement inputs	[3]	0.95		0.65
Fixed deferred indexed annuity embedded derivatives [Member] | Minimum [Member] | Discounted cash flow [Member] | Level 3 [Member] | Surrender rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, measurement inputs		0.000		0.000
Fixed deferred indexed annuity embedded derivatives [Member] | Maximum [Member] | Discounted cash flow [Member] | Level 3 [Member] | Surrender rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, measurement inputs		0.500		0.500
Fixed deferred indexed annuity embedded derivatives [Member] | Weighted average [Member] | Discounted cash flow [Member] | Level 3 [Member] | Nonperformance risk [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, measurement inputs	[3]	0.95
Fixed deferred indexed annuity embedded derivatives [Member] | Weighted average [Member] | Discounted cash flow [Member] | Level 3 [Member] | Surrender rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, measurement inputs	[4]	0.014
GMWB and GMAB embedded derivatives [Member] | Discounted cash flow [Member] | Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, fair value		$ 3,129		$ 763
GMWB and GMAB embedded derivatives [Member] | Discounted cash flow [Member] | Level 3 [Member] | Nonperformance risk [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, measurement inputs	[3]	0.95
GMWB and GMAB embedded derivatives [Member] | Minimum [Member] | Discounted cash flow [Member] | Level 3 [Member] | Surrender rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, measurement inputs		0.001		0.001
GMWB and GMAB embedded derivatives [Member] | Minimum [Member] | Discounted cash flow [Member] | Level 3 [Member] | Utilization of guaranteed withdrawals [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, measurement inputs	[5]	0.000		0.000
GMWB and GMAB embedded derivatives [Member] | Minimum [Member] | Discounted cash flow [Member] | Level 3 [Member] | Market volatility [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, measurement inputs	[6]	0.046		0.037
GMWB and GMAB embedded derivatives [Member] | Maximum [Member] | Discounted cash flow [Member] | Level 3 [Member] | Surrender rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, measurement inputs		0.735		0.735
GMWB and GMAB embedded derivatives [Member] | Maximum [Member] | Discounted cash flow [Member] | Level 3 [Member] | Utilization of guaranteed withdrawals [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, measurement inputs	[5]	0.360		0.360
GMWB and GMAB embedded derivatives [Member] | Maximum [Member] | Discounted cash flow [Member] | Level 3 [Member] | Market volatility [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, measurement inputs	[6]	0.180		0.159
GMWB and GMAB embedded derivatives [Member] | Weighted average [Member] | Discounted cash flow [Member] | Level 3 [Member] | Nonperformance risk [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, measurement inputs	[3]	0.95
GMWB and GMAB embedded derivatives [Member] | Weighted average [Member] | Discounted cash flow [Member] | Level 3 [Member] | Surrender rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, measurement inputs	[4]	0.036
GMWB and GMAB embedded derivatives [Member] | Weighted average [Member] | Discounted cash flow [Member] | Level 3 [Member] | Utilization of guaranteed withdrawals [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, measurement inputs	[5],[7]	0.110
GMWB and GMAB embedded derivatives [Member] | Weighted average [Member] | Discounted cash flow [Member] | Level 3 [Member] | Market volatility [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, measurement inputs	[6],[8]	0.119
Structured annuity embedded derivatives [Member] | Discounted cash flow [Member] | Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, fair value		$ 9
Structured annuity embedded derivatives [Member] | Discounted cash flow [Member] | Level 3 [Member] | Nonperformance risk [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, measurement inputs	[3]	0.95		0.65
Structured annuity embedded derivatives [Member] | Minimum [Member] | Discounted cash flow [Member] | Level 3 [Member] | Surrender rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, measurement inputs		0.008
Structured annuity embedded derivatives [Member] | Maximum [Member] | Discounted cash flow [Member] | Level 3 [Member] | Surrender rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, measurement inputs		0.400
Structured annuity embedded derivatives [Member] | Weighted average [Member] | Discounted cash flow [Member] | Level 3 [Member] | Nonperformance risk [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, measurement inputs	[3]	0.95
Structured annuity embedded derivatives [Member] | Weighted average [Member] | Discounted cash flow [Member] | Level 3 [Member] | Surrender rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivatives, measurement inputs	[4]	0.009

[1] The weighted average for the spread to U.S. Treasuries for corporate debt securities (private placements) is weighted based on the security’s market value as a percentage of the aggregate market value of the securities.

[2] The weighted average for the spread to swap rates for asset backed securities is calculated as the sum of each tranche’s balance multiplied by its spread to swap divided by the aggregate balances of the tranches.

[3] The nonperformance risk is the spread added to the observable interest rates used in the valuation of the embedded derivatives.

[4] The weighted average surrender rate is weighted based on the benefit base of each contract and represents the average assumption in the current year including the effect of a dynamic surrender formula.

[5] The utilization of guaranteed withdrawals represents the percentage of contractholders that will begin withdrawing in any given year.

[6] Market volatility is implied volatility of fund of funds and managed volatility funds.

[7] The weighted average utilization rate represents the average assumption for the current year, weighting each policy evenly. The calculation excludes policies that have already started taking withdrawals.

[8] The weighted average market volatility represents the average volatility across all contracts, weighted by the size of the guaranteed benefit.