Investments (Internal Credit Rating Disclosure) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	$ 6,537	$ 5,861
High Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	3,924	3,438
Internal Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	2,453	2,271
Average Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	120	111
Watch List [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	4	4
Internal Noninvestment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	36	37
Year Of Origination Prior Periods [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	2,363	1,472
Year Of Origination Prior Periods [Member] | High Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	1,686	1,008
Year Of Origination Prior Periods [Member] | Internal Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	580	368
Year Of Origination Prior Periods [Member] | Average Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	57	55
Year Of Origination Prior Periods [Member] | Watch List [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	4	4
Year Of Origination Prior Periods [Member] | Internal Noninvestment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	36	37
Year Of Origination 2016 [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate		860
Year Of Origination 2016 [Member] | High Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate		574
Year Of Origination 2016 [Member] | Internal Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate		249
Year Of Origination 2016 [Member] | Average Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate		37
Year Of Origination 2016 [Member] | Watch List [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate		0
Year Of Origination 2016 [Member] | Internal Noninvestment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate		0
Year Of Origination 2017 [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	721	762
Year Of Origination 2017 [Member] | High Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	304	336
Year Of Origination 2017 [Member] | Internal Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	399	407
Year Of Origination 2017 [Member] | Average Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	18	19
Year Of Origination 2017 [Member] | Watch List [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	0	0
Year Of Origination 2017 [Member] | Internal Noninvestment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	0	0
Year Of Origination 2018 [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	878	892
Year Of Origination 2018 [Member] | High Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	468	493
Year Of Origination 2018 [Member] | Internal Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	371	399
Year Of Origination 2018 [Member] | Average Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	39	0
Year Of Origination 2018 [Member] | Watch List [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	0	0
Year Of Origination 2018 [Member] | Internal Noninvestment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	0	0
Year Of Origination 2019 [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	1,043	1,112
Year Of Origination 2019 [Member] | High Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	569	616
Year Of Origination 2019 [Member] | Internal Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	474	496
Year Of Origination 2019 [Member] | Average Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	0	0
Year Of Origination 2019 [Member] | Watch List [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	0	0
Year Of Origination 2019 [Member] | Internal Noninvestment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	0	0
Year Of Origination 2020 [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	772	763
Year Of Origination 2020 [Member] | High Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	406	411
Year Of Origination 2020 [Member] | Internal Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	366	352
Year Of Origination 2020 [Member] | Average Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	0	0
Year Of Origination 2020 [Member] | Watch List [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	0	0
Year Of Origination 2020 [Member] | Internal Noninvestment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	0	$ 0
Year Of Origination 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	760
Year Of Origination 2021 | High Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	491
Year Of Origination 2021 | Internal Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	263
Year Of Origination 2021 | Average Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	6
Year Of Origination 2021 | Watch List [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	0
Year Of Origination 2021 | Internal Noninvestment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	$ 0