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Reinsurance - Transactions (Details) - USD ($) $ in Millions	Jul. 17, 2020	Jun. 30, 2020	Jun. 01, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Effects of Reinsurance [Line Items]
Liabilities		$ 167,602		$ 132,734
Assets		183,241		146,875
Deferred Policy Acquisition Cost		3,623		3,274	$ 3,503	$ 3,921
Interest sensitive contract liabilities		(135,537)		(102,745)
Future policy benefits (related party: 2018 – $928; portion at fair value: 2018 – $2,249 and 2017 – $2,428)		(24,596)		(23,330)
Related Party
Effects of Reinsurance [Line Items]
Interest sensitive contract liabilities		(14,609)		(15,285)
Future policy benefits (related party: 2018 – $928; portion at fair value: 2018 – $2,249 and 2017 – $2,428)		$ (1,446)		$ (1,302)
Reinsurance Agreement [Member]
Effects of Reinsurance [Line Items]
Liabilities			$ 27,439
Assets			28,805
Interest sensitive contract liabilities			$ (1,366)
Subsequent Event \| Reinsurance Agreement [Member]
Effects of Reinsurance [Line Items]
Equity Securities without Readily Determinable Fair Value, Amount	$ 500