Shareholders' Equity And Dividend Restrictions (Change In AOCI Includes Changes In Unrealized Gains And Losses On Investments And Pension Obligations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2020	Jan. 01, 2019	Jan. 01, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income, Before Tax
Pension obligations OCI	$ (32)	$ 7	$ (4)
Accumulated Other Comprehensive Income, Net of Tax
AOCI, balance at the beginning of the period	448
AOCI, balance at the end of the period	769	448
Accumulated Net Unrealized Investment Gain (Loss)
Accumulated Other Comprehensive Income, Before Tax
AOCI, balance at the beginning of the period	590	46	3,540
Cumulative effect of new accounting principle, before tax		0	0				$ (3,155)
Adjusted AOCI, beginning of period		590	46				385
OCI before investment gains and losses, net, recognized in net income	371	545	(334)
Investment gains and losses, net, recognized in net income	65	(1)	(5)
OCI	436	544	(339)
AOCI, balance at the end of the period	1,026	590	46
Accumulated Other Comprehensive Income, Income Tax
AOCI, balance at the beginning of the period	123	9	733
Cumulative effect of new account principle, tax		0	0				(652)
Adjusted AOCI, beginning of period		123	9				81
OCI before investment gains and losses, net, recognized in net income	78	115	(71)
Investment gains and losses, net, recognized in net income	14	(1)	(1)
OCI	92	114	(72)
AOCI, balance at the end of the period	215	123	9
Accumulated Other Comprehensive Income, Net of Tax
AOCI, balance at the beginning of the period	467	37	2,807
Unrealized gains reclassified to retained earnings for ASU 2016-01, after tax		0	0				(2,503)
Adjusted AOCI, beginning of period		467	37				304
OCI before investment gains and losses, net, recognized in net income	293	430	(263)
Investment gains and losses, net, recognized in net income	51	0	(4)
OCI	344	430	(267)
AOCI, balance at the end of the period	811	467	37
Accumulated Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income, Before Tax
AOCI, balance at the beginning of the period	(9)	(16)	(12)
OCI before investment gains and losses, net, recognized in net income	(35)	6	(5)
Investment gains and losses, net, recognized in net income	3	1	1
OCI	(32)	7	(4)
AOCI, balance at the end of the period	(41)	(9)	(16)
Accumulated Other Comprehensive Income, Income Tax
AOCI, balance at the beginning of the period	0	(2)	(1)
OCI before investment gains and losses, net, recognized in net income	(7)	2	(1)
Investment gains and losses, net, recognized in net income	0	0	0
OCI	(7)	2	(1)
AOCI, balance at the end of the period	(7)	0	(2)
Accumulated Other Comprehensive Income, Net of Tax
AOCI, balance at the beginning of the period	(9)	(14)	(11)
OCI before investment gains and losses, net, recognized in net income	(28)	4	(4)
Investment gains and losses, net, recognized in net income	3	1	1
OCI	(25)	5	(3)
AOCI, balance at the end of the period	(34)	(9)	(14)
Accumulated Net Unrealized Gain (Loss) on Deferred Costs, Reserves And Other
Accumulated Other Comprehensive Income, Before Tax
AOCI, balance at the beginning of the period	(13)	(1)	(10)
OCI before investment gains and losses, net, recognized in net income	3	(15)	(3)
Investment gains and losses, net, recognized in net income	0	3	12
OCI	3	(12)	9
AOCI, balance at the end of the period	(10)	(13)	(1)
Accumulated Other Comprehensive Income, Income Tax
AOCI, balance at the beginning of the period	(3)	0	(2)
OCI before investment gains and losses, net, recognized in net income	1	(3)	(1)
Investment gains and losses, net, recognized in net income	0	0	3
OCI	1	(3)	2
AOCI, balance at the end of the period	(2)	(3)	0
Accumulated Other Comprehensive Income, Net of Tax
AOCI, balance at the beginning of the period	(10)	(1)	(8)
OCI before investment gains and losses, net, recognized in net income	2	(12)	(2)
Investment gains and losses, net, recognized in net income	0	3	9
OCI	2	(9)	7
AOCI, balance at the end of the period	(8)	(10)	(1)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income, Before Tax
AOCI, balance at the beginning of the period	568	29	3,518
Cumulative effect of new accounting principle, before tax				$ 0	$ 0	$ (3,155)
Adjusted AOCI, beginning of period		568	29				363
Investments OCI	436	544	(339)
Pension obligations OCI	(32)	7	(4)
Life deferred acquisition costs, life policy reserves and other OCI	3	(12)	9
Total OCI	407	539	(334)
AOCI, balance at the end of the period	975	568	29
Accumulated Other Comprehensive Income, Income Tax
AOCI, balance at the beginning of the period	120	7	730
Cumulative effect of new account principle, tax				0	0	(652)
Adjusted AOCI, beginning of period		120	7				78
Investments OCI	92	114	(72)
Pension obligations OCI	(7)	2	(1)
Life deferred acquisition costs, life policy reserves and other OCI	1	(3)	2
Total OCI	86	113	(71)
AOCI, balance at the end of the period	206	120	7
Accumulated Other Comprehensive Income, Net of Tax
AOCI, balance at the beginning of the period	448	22	2,788
Unrealized gains reclassified to retained earnings for ASU 2016-01, after tax		0	0	$ 0	$ 0	$ (2,503)	(2,503)
Adjusted AOCI, beginning of period		448	22				$ 285
Investments OCI	344	430	(267)
Pension obligations OCI	(25)	5	(3)
Life deferred acquisition costs, life policy reserves and other OCI	2	(9)	7
Total OCI	321	426	(263)
AOCI, balance at the end of the period	$ 769	$ 448	$ 22