Fair Value of Financial Instruments (Fair Value Inputs Quantitative Information) (Details) - Significant Unobservable Inputs (Level 3) [Member] - Discounted Cash Flow Valuation Technique [Member] $ in Millions	Mar. 31, 2020 USD ($) item
Corporate Bonds [Member] | Fixed Maturity AFS Securities [Member]
Assets Fair Value Disclosure [Abstract]
Assets Fair Value Disclosure | $	$ 2,680
Corporate Bonds [Member] | Maximum [Member] | Fixed Maturity AFS Securities [Member] | Liquidity/Duration Adjustment [Member]
Liabilities Fair Value Disclosure [Abstract]
Fixed maturity AFS and trading securities, measurement input	0.188
Corporate Bonds [Member] | Minimum [Member] | Fixed Maturity AFS Securities [Member] | Liquidity/Duration Adjustment [Member]
Liabilities Fair Value Disclosure [Abstract]
Fixed maturity AFS and trading securities, measurement input	0.007
Corporate Bonds [Member] | Weighted Average [Member] | Fixed Maturity AFS Securities [Member] | Liquidity/Duration Adjustment [Member]
Liabilities Fair Value Disclosure [Abstract]
Fixed maturity AFS and trading securities, measurement input	0.029
Foreign Government Bonds [Member] | Fixed Maturity AFS Securities [Member]
Assets Fair Value Disclosure [Abstract]
Assets Fair Value Disclosure | $	$ 47
Foreign Government Bonds [Member] | Maximum [Member] | Fixed Maturity AFS Securities [Member] | Liquidity/Duration Adjustment [Member]
Liabilities Fair Value Disclosure [Abstract]
Fixed maturity AFS and trading securities, measurement input	0.080
Foreign Government Bonds [Member] | Minimum [Member] | Fixed Maturity AFS Securities [Member] | Liquidity/Duration Adjustment [Member]
Liabilities Fair Value Disclosure [Abstract]
Fixed maturity AFS and trading securities, measurement input	0.053
Foreign Government Bonds [Member] | Weighted Average [Member] | Fixed Maturity AFS Securities [Member] | Liquidity/Duration Adjustment [Member]
Liabilities Fair Value Disclosure [Abstract]
Fixed maturity AFS and trading securities, measurement input	0.068
ABS [Member] | Fixed Maturity AFS Securities [Member]
Assets Fair Value Disclosure [Abstract]
Assets Fair Value Disclosure | $	$ 20
ABS [Member] | Maximum [Member] | Fixed Maturity AFS Securities [Member] | Liquidity/Duration Adjustment [Member]
Liabilities Fair Value Disclosure [Abstract]
Fixed maturity AFS and trading securities, measurement input	0.060
ABS [Member] | Minimum [Member] | Fixed Maturity AFS Securities [Member] | Liquidity/Duration Adjustment [Member]
Liabilities Fair Value Disclosure [Abstract]
Fixed maturity AFS and trading securities, measurement input	0.060
ABS [Member] | Weighted Average [Member] | Fixed Maturity AFS Securities [Member] | Liquidity/Duration Adjustment [Member]
Liabilities Fair Value Disclosure [Abstract]
Fixed maturity AFS and trading securities, measurement input	0.060
Hybrid And Redeemable Preferred Securities [Member] | Fixed Maturity AFS Securities [Member]
Assets Fair Value Disclosure [Abstract]
Assets Fair Value Disclosure | $	$ 4
Hybrid And Redeemable Preferred Securities [Member] | Maximum [Member] | Fixed Maturity AFS Securities [Member] | Liquidity/Duration Adjustment [Member]
Liabilities Fair Value Disclosure [Abstract]
Fixed maturity AFS and trading securities, measurement input	0.030
Hybrid And Redeemable Preferred Securities [Member] | Minimum [Member] | Fixed Maturity AFS Securities [Member] | Liquidity/Duration Adjustment [Member]
Liabilities Fair Value Disclosure [Abstract]
Fixed maturity AFS and trading securities, measurement input	0.030
Hybrid And Redeemable Preferred Securities [Member] | Weighted Average [Member] | Fixed Maturity AFS Securities [Member] | Liquidity/Duration Adjustment [Member]
Liabilities Fair Value Disclosure [Abstract]
Fixed maturity AFS and trading securities, measurement input	0.030
Equity Securities [Member] | Fixed Maturity AFS Securities [Member]
Assets Fair Value Disclosure [Abstract]
Assets Fair Value Disclosure | $	$ 20
Equity Securities [Member] | Maximum [Member] | Fixed Maturity AFS Securities [Member] | Liquidity/Duration Adjustment [Member]
Liabilities Fair Value Disclosure [Abstract]
Equity securities, measurement input	0.073
Equity Securities [Member] | Minimum [Member] | Fixed Maturity AFS Securities [Member] | Liquidity/Duration Adjustment [Member]
Liabilities Fair Value Disclosure [Abstract]
Equity securities, measurement input	0.045
Equity Securities [Member] | Weighted Average [Member] | Fixed Maturity AFS Securities [Member] | Liquidity/Duration Adjustment [Member]
Liabilities Fair Value Disclosure [Abstract]
Equity securities, measurement input	0.067
GLB Ceded Embedded Derivatives [Member] | Other Assets [Member]
Assets Fair Value Disclosure [Abstract]
Assets Fair Value Disclosure | $	$ 4,589
GLB Ceded Embedded Derivatives [Member] | Maximum [Member] | Other Assets [Member] | Lapse Rate [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative assets, measurement input	0.30
GLB Ceded Embedded Derivatives [Member] | Minimum [Member] | Other Assets [Member] | Lapse Rate [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative assets, measurement input	0.01
GLB Ceded Embedded Derivatives [Member] | Weighted Average [Member] | Other Assets [Member] | Utilization Of Guaranteed Withdrawls [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative assets, measurement input	0.94
GLB Ceded Embedded Derivatives [Member] | Weighted Average [Member] | Other Assets [Member] | NPR [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative assets, measurement input	0.0027
GLB Ceded Embedded Derivatives [Member] | Weighted Average [Member] | Other Assets [Member] | Volatility [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative assets, measurement input	0.1372
GLB Direct And Ceded Embedded Derivative [Member] | Maximum [Member] | Other Assets [Member] | Utilization Of Guaranteed Withdrawls [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative assets, measurement input	1
GLB Direct And Ceded Embedded Derivative [Member] | Maximum [Member] | Other Assets [Member] | Claims Utilization Factor [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative assets, measurement input	1
GLB Direct And Ceded Embedded Derivative [Member] | Maximum [Member] | Other Assets [Member] | Premiums Utilization Factor [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative assets, measurement input	1.15
GLB Direct And Ceded Embedded Derivative [Member] | Maximum [Member] | Other Assets [Member] | NPR [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative assets, measurement input	0.0035
GLB Direct And Ceded Embedded Derivative [Member] | Maximum [Member] | Other Assets [Member] | Volatility [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative assets, measurement input	0.28
GLB Direct And Ceded Embedded Derivative [Member] | Minimum [Member] | Other Assets [Member] | Utilization Of Guaranteed Withdrawls [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative assets, measurement input	0.85
GLB Direct And Ceded Embedded Derivative [Member] | Minimum [Member] | Other Assets [Member] | Claims Utilization Factor [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative assets, measurement input	0.60
GLB Direct And Ceded Embedded Derivative [Member] | Minimum [Member] | Other Assets [Member] | Premiums Utilization Factor [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative assets, measurement input	0.80
GLB Direct And Ceded Embedded Derivative [Member] | Minimum [Member] | Other Assets [Member] | NPR [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative assets, measurement input	0.0003
GLB Direct And Ceded Embedded Derivative [Member] | Minimum [Member] | Other Assets [Member] | Volatility [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative assets, measurement input	0.01
Indexed Annuity And IUL Contracts [Member] | Other Assets [Member]
Assets Fair Value Disclosure [Abstract]
Assets Fair Value Disclosure | $	$ 799
Indexed Annuity And IUL Contracts [Member] | Maximum [Member] | Other Assets [Member] | Lapse Rate [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative assets, measurement input	0.09
Indexed Annuity And IUL Contracts [Member] | Minimum [Member] | Other Assets [Member] | Lapse Rate [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative assets, measurement input	0.01
Future contract benefits - indexed annuity and IUL contracts embedded derivatives | Future Contract Benefits [Member]
Liabilities Fair Value Disclosure [Abstract]
Liabilities measured at fair value | $	$ (1,380)
Future contract benefits - indexed annuity and IUL contracts embedded derivatives | Maximum [Member] | Future Contract Benefits [Member] | Lapse Rate [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative liability, measurement input	0.09
Future contract benefits - indexed annuity and IUL contracts embedded derivatives | Minimum [Member] | Future Contract Benefits [Member] | Lapse Rate [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative liability, measurement input	0.01
GLB Direct Embedded Derivatives [Member] | Other Liabilities [Member]
Liabilities Fair Value Disclosure [Abstract]
Liabilities measured at fair value | $	$ (4,596)
GLB Direct Embedded Derivatives [Member] | Maximum [Member] | Other Liabilities [Member] | Lapse Rate [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative liability, measurement input	0.30
GLB Direct Embedded Derivatives [Member] | Maximum [Member] | Other Liabilities [Member] | Utilization Of Guaranteed Withdrawls [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative liability, measurement input	1
GLB Direct Embedded Derivatives [Member] | Maximum [Member] | Other Liabilities [Member] | Claims Utilization Factor [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative liability, measurement input	1
GLB Direct Embedded Derivatives [Member] | Maximum [Member] | Other Liabilities [Member] | Premiums Utilization Factor [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative liability, measurement input	1.15
GLB Direct Embedded Derivatives [Member] | Maximum [Member] | Other Liabilities [Member] | NPR [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative liability, measurement input	0.0035
GLB Direct Embedded Derivatives [Member] | Maximum [Member] | Other Liabilities [Member] | Volatility [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative liability, measurement input	0.28
GLB Direct Embedded Derivatives [Member] | Minimum [Member] | Other Liabilities [Member] | Lapse Rate [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative liability, measurement input	0.01
GLB Direct Embedded Derivatives [Member] | Minimum [Member] | Other Liabilities [Member] | Utilization Of Guaranteed Withdrawls [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative liability, measurement input	0.85
GLB Direct Embedded Derivatives [Member] | Minimum [Member] | Other Liabilities [Member] | Claims Utilization Factor [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative liability, measurement input	0.60
GLB Direct Embedded Derivatives [Member] | Minimum [Member] | Other Liabilities [Member] | Premiums Utilization Factor [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative liability, measurement input	0.80
GLB Direct Embedded Derivatives [Member] | Minimum [Member] | Other Liabilities [Member] | NPR [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative liability, measurement input	0.0003
GLB Direct Embedded Derivatives [Member] | Minimum [Member] | Other Liabilities [Member] | Volatility [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative liability, measurement input	0.01
GLB Direct Embedded Derivatives [Member] | Weighted Average [Member] | Other Liabilities [Member] | Utilization Of Guaranteed Withdrawls [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative liability, measurement input	0.94
GLB Direct Embedded Derivatives [Member] | Weighted Average [Member] | Other Liabilities [Member] | NPR [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative liability, measurement input	0.0027
GLB Direct Embedded Derivatives [Member] | Weighted Average [Member] | Other Liabilities [Member] | Volatility [Member]
Liabilities Fair Value Disclosure [Abstract]
Derivative liability, measurement input	0.1372