Investments (Residential Mortgage Loans By Year Of Origination) (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Financing Receivable, Credit Quality Indicator [Line Items]
Amount originated in current year		$ 1,536
Amount originated in prior year		3,401
Amount originated 2 years prior		2,583
Amount originated 3 years prior		1,955
Amount originated 4 years prior		1,909
Amount originated 5 or more years prior		4,851
Total		16,235
Residential [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Amount originated in current year	$ 71	184
Amount originated in prior year	203	366
Amount originated 2 years prior	337	187
Amount originated 3 years prior	167
Total	778	737
Performing [Member] | Residential [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Amount originated in current year	71	176
Amount originated in prior year	197	315
Amount originated 2 years prior	295	175
Amount originated 3 years prior	158
Total	721	666
Nonperforming [Member] | Residential [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Amount originated in current year		8
Amount originated in prior year	6	51
Amount originated 2 years prior	42	12
Amount originated 3 years prior	9
Total	$ 57	$ 71