Investments (Current And Long-Term Fixed Maturity Securities, Available-For-Sale) (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	$ 30,724	$ 29,015
Gross Unrealized Gains	104	76
Gross Unrealized Losses	(2,025)	(2,378)
Debt Securities, Available-for-Sale, Allowance for Credit Loss	(7)	(9)
Available-for-sale Securities	28,796	26,704
United States Government Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	1,957	1,502
Gross Unrealized Gains	1	2
Gross Unrealized Losses	(75)	(103)
Debt Securities, Available-for-Sale, Allowance for Credit Loss	0	0
Available-for-sale Securities	1,883	1,401
Government Sponsored Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	94	82
Gross Unrealized Gains	1	1
Gross Unrealized Losses	(4)	(5)
Debt Securities, Available-for-Sale, Allowance for Credit Loss	0	0
Available-for-sale Securities	91	78
Foreign Government Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	337	321
Gross Unrealized Gains	2	1
Gross Unrealized Losses	(41)	(46)
Debt Securities, Available-for-Sale, Allowance for Credit Loss	(1)	(2)
Available-for-sale Securities	297	274
States, Municipalities And Political Subdivisions [Member]
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	3,957	4,389
Gross Unrealized Gains	22	19
Gross Unrealized Losses	(207)	(265)
Debt Securities, Available-for-Sale, Allowance for Credit Loss	0	0
Available-for-sale Securities	3,772	4,143
Corporate Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	14,276	13,721
Gross Unrealized Gains	50	31
Gross Unrealized Losses	(997)	(1,218)
Debt Securities, Available-for-Sale, Allowance for Credit Loss	(4)	(5)
Available-for-sale Securities	13,325	12,529
Residential Mortgage-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	3,617	2,978
Gross Unrealized Gains	11	9
Gross Unrealized Losses	(313)	(324)
Debt Securities, Available-for-Sale, Allowance for Credit Loss	0	0
Available-for-sale Securities	3,315	2,663
Commercial Mortgage-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	2,262	2,055
Gross Unrealized Gains	2	1
Gross Unrealized Losses	(180)	(176)
Debt Securities, Available-for-Sale, Allowance for Credit Loss	(2)	(2)
Available-for-sale Securities	2,082	1,878
Other Asset-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	4,224	3,967
Gross Unrealized Gains	15	12
Gross Unrealized Losses	(208)	(241)
Debt Securities, Available-for-Sale, Allowance for Credit Loss	0	0
Available-for-sale Securities	$ 4,031	$ 3,738