Income Taxes (Differences Between The 35 Percent Statutory Income Tax Rate And Effective Income Tax Rate) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Tax at statutory rate:	$ 53	$ 256	$ 284
Tax at statutory rate (percentage):	21.00%	35.00%	35.00%
Increase (decrease) resulting from:
Tax-exempt income from municipal bonds	$ (20)	$ (36)	$ (34)
Dividend received exclusion	(15)	(34)	(33)
Effective Income Tax Rate Reconciliation, Tax Accounting Method Changes, Amount	(50)	0	0
Deferred tax benefit due to tax rate change	0	(495)	0
Other	(4)	(6)	4
Total provision (benefit) for income taxes	$ (36)	$ (315)	$ 221
Tax at statutory rate:
Tax-exempt income from municipal bonds (percentage)	(8.00%)	(4.90%)	(4.20%)
Dividend received exclusion (percentage)	(6.00%)	(4.70%)	(4.10%)
Effective Income Tax Rate Reconciliation, Tax Accounting Method Changes, Percent	(19.90%)	0.00%	0.00%
Deferred tax benefit due to tax rate change	0.00%	(67.80%)	0.00%
Other (percentage)	(1.40%)	(0.80%)	0.50%
Effective tax, percentage	(14.30%)	(43.20%)	27.20%