Investments (Commercial Mortgage Loans By Year Of Origination) (Details) $ in Millions	Sep. 30, 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	$ 1,803
Amount originated in prior year	1,509
Amount originated 2 years prior	3,302
Amount originated 3 years prior	2,490
Amount originated 4 years prior	1,894
Amount originated 5 or more years prior	6,101
Total	17,099
Commercial [Member] | Loan-to-value ratio, less than 65% [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Amount originated in current year	1,676
Amount originated in prior year	1,365
Amount originated 2 years prior	3,009
Amount originated 3 years prior	2,298
Amount originated 4 years prior	1,717
Amount originated 5 or more years prior	5,869
Total	$ 15,934
Ratio of originations in current year | item	3.07
Ratio of originations in prior year | item	3.03
Ratio of originations 2 years prior | item	2.19
Ratio of originations 3 years prior | item	2.15
Ratio of originations 4 years prior | item	2.32
Ratio of originations 5 or more years prior | item	2.40
Commercial [Member] | Loan-to-value ratio, 65% to 74% [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Amount originated in current year	$ 127
Amount originated in prior year	144
Amount originated 2 years prior	293
Amount originated 3 years prior	177
Amount originated 4 years prior	150
Amount originated 5 or more years prior	195
Total	$ 1,086
Ratio of originations in current year | item	1.76
Ratio of originations in prior year | item	1.67
Ratio of originations 2 years prior | item	1.62
Ratio of originations 3 years prior | item	1.58
Ratio of originations 4 years prior | item	1.74
Ratio of originations 5 or more years prior | item	1.77
Commercial [Member] | Loan-to-value ratio, 75% to 100% [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Amount originated 3 years prior	$ 15
Amount originated 4 years prior	27
Amount originated 5 or more years prior	37
Total	$ 79
Ratio of originations 3 years prior | item	1.02
Ratio of originations 4 years prior | item	0.96
Ratio of originations 5 or more years prior | item	0.78