Fair Value, Significant Unobservable Inputs (Details) $ in Millions	Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)
Quantitative Information About the Significant Unobservable Inputs [Abstract]
Estimated fair value	$ 42,799	$ 42,240
Level 3 [Member] \| Fixed Maturity Securities [Member]
Quantitative Information About the Significant Unobservable Inputs [Abstract]
Estimated fair value	$ 693	$ 525
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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	0.09	0.06
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	0.03	0.02

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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