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, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019	Jan. 01, 2018	Jan. 01, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income, Before Tax
Pension obligations OCI	$ 7	$ (4)	$ 14
Accumulated Other Comprehensive Income, Net of Tax
AOCI, balance at the beginning of the period	22
Unrealized gains reclassified to retained earnings for ASU 2016-01, after tax		2,503
AOCI, balance at the end of the period	448	22
Accumulated Net Unrealized Investment Gain (Loss)
Accumulated Other Comprehensive Income, Before Tax
AOCI, balance at the beginning of the period	46	3,540	2,625
Cumulative effect of new accounting principle, before tax		0	(3,155)				$ 0
Adjusted AOCI, beginning of period		46	385				2,625
OCI before investment gains and losses, net, recognized in net income	545	(334)	1,054
Investment gains and losses, net, recognized in net income	(1)	(5)	(139)
OCI	544	(339)	915
AOCI, balance at the end of the period	590	46	3,540
Accumulated Other Comprehensive Income, Income Tax
AOCI, balance at the beginning of the period	9	733	908
Cumulative effect of new account principle, tax		0	(652)				0
Adjusted AOCI, beginning of period		9	81				908
OCI before investment gains and losses, net, recognized in net income	115	(71)	366
Investment gains and losses, net, recognized in net income	(1)	(1)	(49)
OCI	114	(72)	317
AOCI, balance at the end of the period	123	9	733
Accumulated Other Comprehensive Income, Net of Tax
AOCI, balance at the beginning of the period	37	2,807	1,717
Unrealized gains reclassified to retained earnings for ASU 2016-01, after tax		0	(2,503)				0
Adjusted AOCI, beginning of period		37	304				1,717
OCI before investment gains and losses, net, recognized in net income	430	(263)	688
Investment gains and losses, net, recognized in net income	0	(4)	(90)
OCI	430	(267)	598
AOCI, balance at the end of the period	467	37	2,807
Accumulated Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income, Before Tax
AOCI, balance at the beginning of the period	(16)	(12)	(26)
OCI before investment gains and losses, net, recognized in net income	6	(5)	12
Investment gains and losses, net, recognized in net income	1	1	2
OCI	7	(4)	14
AOCI, balance at the end of the period	(9)	(16)	(12)
Accumulated Other Comprehensive Income, Income Tax
AOCI, balance at the beginning of the period	(2)	(1)	(8)
OCI before investment gains and losses, net, recognized in net income	2	(1)	6
Investment gains and losses, net, recognized in net income	0	0	1
OCI	2	(1)	7
AOCI, balance at the end of the period	0	(2)	(1)
Accumulated Other Comprehensive Income, Net of Tax
AOCI, balance at the beginning of the period	(14)	(11)	(18)
OCI before investment gains and losses, net, recognized in net income	4	(4)	6
Investment gains and losses, net, recognized in net income	1	1	1
OCI	5	(3)	7
AOCI, balance at the end of the period	(9)	(14)	(11)
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	(1)	(10)	(9)
OCI before investment gains and losses, net, recognized in net income	(15)	(3)	8
Investment gains and losses, net, recognized in net income	3	12	(9)
OCI	(12)	9	(1)
AOCI, balance at the end of the period	(13)	(1)	(10)
Accumulated Other Comprehensive Income, Income Tax
AOCI, balance at the beginning of the period	0	(2)	(3)
OCI before investment gains and losses, net, recognized in net income	(3)	(1)	5
Investment gains and losses, net, recognized in net income	0	3	(4)
OCI	(3)	2	1
AOCI, balance at the end of the period	(3)	0	(2)
Accumulated Other Comprehensive Income, Net of Tax
AOCI, balance at the beginning of the period	(1)	(8)	(6)
OCI before investment gains and losses, net, recognized in net income	(12)	(2)	3
Investment gains and losses, net, recognized in net income	3	9	(5)
OCI	(9)	7	(2)
AOCI, balance at the end of the period	(10)	(1)	(8)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income, Before Tax
AOCI, balance at the beginning of the period	29	3,518	2,590
Cumulative effect of new accounting principle, before tax				$ 0	$ (3,155)	$ 0
Adjusted AOCI, beginning of period		29	363				2,590
Investments OCI	544	(339)	915
Pension obligations OCI	7	(4)	14
Life deferred acquisition costs, life policy reserves and other OCI	(12)	9	(1)
Total OCI	539	(334)	928
AOCI, balance at the end of the period	568	29	3,518
Accumulated Other Comprehensive Income, Income Tax
AOCI, balance at the beginning of the period	7	730	897
Cumulative effect of new account principle, tax				0	(652)	0
Adjusted AOCI, beginning of period		7	78				897
Investments OCI	114	(72)	317
Pension obligations OCI	2	(1)	7
Life deferred acquisition costs, life policy reserves and other OCI	(3)	2	1
Total OCI	113	(71)	325
AOCI, balance at the end of the period	120	7	730
Accumulated Other Comprehensive Income, Net of Tax
AOCI, balance at the beginning of the period	22	2,788	1,693
Unrealized gains reclassified to retained earnings for ASU 2016-01, after tax		0	(2,503)	$ 0	$ (2,503)	$ 0	0
Adjusted AOCI, beginning of period		22	285				$ 1,693
Investments OCI	430	(267)	598
Pension obligations OCI	5	(3)	7
Life deferred acquisition costs, life policy reserves and other OCI	(9)	7	(2)
Total OCI	426	(263)	603
AOCI, balance at the end of the period	448	22	2,788
New Accounting Pronouncement, Early Adoption, Effect | Accounting Standards Update 2018-02 | Accumulated Net Unrealized Investment Gain (Loss)
Accumulated Other Comprehensive Income, Before Tax
Cumulative effect of new accounting principle, before tax	0	0	0
Accumulated Other Comprehensive Income, Income Tax
Cumulative effect of new account principle, tax	0	0	(492)
Accumulated Other Comprehensive Income, Net of Tax
Adjustment to reclassify certain tax effects from AOCI	0	0	492
New Accounting Pronouncement, Early Adoption, Effect | Accounting Standards Update 2018-02 | Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income, Before Tax
Cumulative effect of new accounting principle, before tax	0	0	0
Accumulated Other Comprehensive Income, Income Tax
Cumulative effect of new account principle, tax	0	0	(492)
Accumulated Other Comprehensive Income, Net of Tax
Adjustment to reclassify certain tax effects from AOCI	$ 0	$ 0	$ 492