Investments (Internal Credit Rating Disclosure) (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 6,040	$ 5,727
High Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,745
Internal Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,119
Average Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	155
Watch List [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	4
Internal Noninvestment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	17
Year Of Origination Prior Periods [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,639
Year Of Origination Prior Periods [Member] | High Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,115
Year Of Origination Prior Periods [Member] | Internal Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	409
Year Of Origination Prior Periods [Member] | Average Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	94
Year Of Origination Prior Periods [Member] | Watch List [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	4
Year Of Origination Prior Periods [Member] | Internal Noninvestment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	17
Year Of Origination 2016 [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	899
Year Of Origination 2016 [Member] | High Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	601
Year Of Origination 2016 [Member] | Internal Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	271
Year Of Origination 2016 [Member] | Average Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	27
Year Of Origination 2016 [Member] | Watch List [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Year Of Origination 2016 [Member] | Internal Noninvestment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Year Of Origination 2017 [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	768
Year Of Origination 2017 [Member] | High Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	401
Year Of Origination 2017 [Member] | Internal Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	342
Year Of Origination 2017 [Member] | Average Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	25
Year Of Origination 2017 [Member] | Watch List [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Year Of Origination 2017 [Member] | Internal Noninvestment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Year Of Origination 2018 [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	948
Year Of Origination 2018 [Member] | High Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	622
Year Of Origination 2018 [Member] | Internal Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	317
Year Of Origination 2018 [Member] | Average Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	9
Year Of Origination 2018 [Member] | Watch List [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Year Of Origination 2018 [Member] | Internal Noninvestment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Year Of Origination 2019 [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,191
Year Of Origination 2019 [Member] | High Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	674
Year Of Origination 2019 [Member] | Internal Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	517
Year Of Origination 2019 [Member] | Average Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Year Of Origination 2019 [Member] | Watch List [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Year Of Origination 2019 [Member] | Internal Noninvestment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Year Of Origination 2020 [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	595
Year Of Origination 2020 [Member] | High Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	332
Year Of Origination 2020 [Member] | Internal Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	263
Year Of Origination 2020 [Member] | Average Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Year Of Origination 2020 [Member] | Watch List [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Year Of Origination 2020 [Member] | Internal Noninvestment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 0