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Investments - Investments - ACL on Mortgages (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Dec. 31, 2020	Jan. 01, 2020
Financing Receivable, Allowance for Credit Loss [Line Items]
Retained earnings			$ 14,036	$ 13,918
Commercial Loan [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	$ (38)	$ 0
Financing Receivable, Allowance for Credit Loss	(38)	(21)	$ (34)	$ (38)
Current period provision	(4)	2
Ending balance	$ (34)	$ (21)
Cumulative Effect, Period of Adoption, Adjustment [Member] \| Commercial Loan [Member] \| Accounting Standards Update 2016-13 [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Retained earnings					$ 19
Cumulative Effect, Period of Adoption, Adjusted Balance [Member] \| Commercial Loan [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss					$ (19)