Fair Value, Significant Unobservable Inputs (Details) $ in Millions	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Quantitative Information About the Significant Unobservable Inputs [Abstract]
Estimated fair value	$ 45,069	$ 44,646
Level 3 [Member] | Fixed Maturity Securities [Member]
Quantitative Information About the Significant Unobservable Inputs [Abstract]
Estimated fair value	$ 1,154	$ 966
Level 3 [Member] | Fixed Maturity Securities [Member] | Credit Spread [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Quantitative Information About the Significant Unobservable Inputs [Abstract]
Measurement input	0.01	0.01
Level 3 [Member] | Fixed Maturity Securities [Member] | Credit Spread [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Quantitative Information About the Significant Unobservable Inputs [Abstract]
Measurement input	0.07	0.08
Level 3 [Member] | Fixed Maturity Securities [Member] | Credit Spread [Member] | Discounted Cash Flow [Member] | Weighted Average [Member]
Quantitative Information About the Significant Unobservable Inputs [Abstract]
Measurement input	0.02	0.03