Investments (Commercial Mortgage Loans By Year Of Origination) (Details) $ in Millions	Mar. 31, 2021 USD ($) item	Dec. 31, 2020 USD ($) item
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
Loan-to-value ratio, less than 65% [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Amount originated in current year		1,504
Amount originated in prior year		3,141
Amount originated 2 years prior		2,382
Amount originated 3 years prior		1,786
Amount originated 4 years prior		1,713
Amount originated 5 or more years prior		4,710
Total		$ 15,236
Ratio of originations in current year | item		2.86
Ratio of originations in prior year | item		2.25
Ratio of originations 2 years prior | item		2.16
Ratio of originations 3 years prior | item		2.34
Ratio of originations 4 years prior | item		2.37
Ratio of originations 5 or more years prior | item		2.38
Loan-to-value ratio, 65% to 74% [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Amount originated in current year		$ 32
Amount originated in prior year		258
Amount originated 2 years prior		186
Amount originated 3 years prior		169
Amount originated 4 years prior		174
Amount originated 5 or more years prior		133
Total		$ 952
Ratio of originations in current year | item		1.52
Ratio of originations in prior year | item		1.78
Ratio of originations 2 years prior | item		1.49
Ratio of originations 3 years prior | item		1.73
Ratio of originations 4 years prior | item		1.56
Ratio of originations 5 or more years prior | item		1.95
Loan-to-value ratio, 75% to 100% [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Amount originated in prior year		$ 2
Amount originated 2 years prior		15
Amount originated 4 years prior		22
Amount originated 5 or more years prior		8
Total		$ 47
Ratio of originations in prior year | item		1.74
Ratio of originations 2 years prior | item		0.71
Ratio of originations 4 years prior | item		1.58
Ratio of originations 5 or more years prior | item		1.02
Commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Amount originated in current year	$ 704
Amount originated in prior year	1,520
Amount originated 2 years prior	3,393
Amount originated 3 years prior	2,571
Amount originated 4 years prior	1,933
Amount originated 5 or more years prior	6,546
Total	16,667
Commercial [Member] | Loan-to-value ratio, less than 65% [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Amount originated in current year	679
Amount originated in prior year	1,371
Amount originated 2 years prior	3,050
Amount originated 3 years prior	2,338
Amount originated 4 years prior	1,753
Amount originated 5 or more years prior	6,253
Total	$ 15,444
Ratio of originations in current year | item	2.99
Ratio of originations in prior year | item	3.02
Ratio of originations 2 years prior | item	2.21
Ratio of originations 3 years prior | item	2.15
Ratio of originations 4 years prior | item	2.34
Ratio of originations 5 or more years prior | item	2.39
Commercial [Member] | Loan-to-value ratio, 65% to 74% [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Amount originated in current year	$ 25
Amount originated in prior year	109
Amount originated 2 years prior	318
Amount originated 3 years prior	218
Amount originated 4 years prior	153
Amount originated 5 or more years prior	263
Total	$ 1,086
Ratio of originations in current year | item	1.95
Ratio of originations in prior year | item	1.47
Ratio of originations 2 years prior | item	1.96
Ratio of originations 3 years prior | item	1.55
Ratio of originations 4 years prior | item	1.74
Ratio of originations 5 or more years prior | item	1.75
Commercial [Member] | Loan-to-value ratio, 75% to 100% [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Amount originated in prior year	$ 40
Amount originated 2 years prior	25
Amount originated 3 years prior	15
Amount originated 4 years prior	27
Amount originated 5 or more years prior	30
Total	$ 137
Ratio of originations in prior year | item	2.21
Ratio of originations 2 years prior | item	1.79
Ratio of originations 3 years prior | item	0.76
Ratio of originations 4 years prior | item	0.67
Ratio of originations 5 or more years prior | item	1.40