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, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income, Before Tax
Pension obligations OCI	$ 16	$ (6)	$ (18)
Accumulated Other Comprehensive Income, Income Tax
Income taxes on above of other comprehensive income (loss)	188	(218)	130
Accumulated Other Comprehensive Income, Net of Tax
AOCI, balance at the beginning of the period	1,344
Other comprehensive income (loss) before tax	537	(618)	370
AOCI, balance at the end of the period	1,693	1,344
Accumulated Net Unrealized Investment Gain (Loss)
Accumulated Other Comprehensive Income, Before Tax
AOCI, balance at the beginning of the period	2,094	2,719	2,335
OCI before realized gains (losses) recognized in net income	653	(556)	514
Realized gains (losses) recognized in net income	(122)	(69)	(130)
OCI, portion attributable to Parent	531	(625)	384
AOCI, balance at the end of the period	2,625	2,094	2,719
Accumulated Other Comprehensive Income, Income Tax
AOCI, balance at the beginning of the period	722	942	808
OCI before realized gains (losses) recognized in net income	229	(196)	181
Realized gains (losses) recognized in net income	(43)	(24)	(47)
Income taxes on above of other comprehensive income (loss)	186	(220)	134
AOCI, balance at the end of the period	908	722	942
Accumulated Other Comprehensive Income, Net of Tax
AOCI, balance at the beginning of the period	1,372	1,777	1,527
OCI before realized gains (losses) recognized in net income	424	(360)	333
Realized gains (losses) recognized in net income	(79)	(45)	(83)
Other comprehensive income (loss) before tax	345	(405)	250
AOCI, balance at the end of the period	1,717	1,372	1,777
Accumulated Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income, Before Tax
AOCI, balance at the beginning of the period	(42)	(36)	(18)
OCI before realized gains (losses) recognized in net income	13	(12)	(21)
Realized gains (losses) recognized in net income	3	6	3
OCI, portion attributable to Parent	16	(6)	(18)
AOCI, balance at the end of the period	(26)	(42)	(36)
Accumulated Other Comprehensive Income, Income Tax
AOCI, balance at the beginning of the period	(14)	(12)	(6)
OCI before realized gains (losses) recognized in net income	5	(5)	(7)
Realized gains (losses) recognized in net income	1	3	1
Income taxes on above of other comprehensive income (loss)	6	(2)	(6)
AOCI, balance at the end of the period	(8)	(14)	(12)
Accumulated Other Comprehensive Income, Net of Tax
AOCI, balance at the beginning of the period	(28)	(24)	(12)
OCI before realized gains (losses) recognized in net income	8	(7)	(14)
Realized gains (losses) recognized in net income	2	3	2
Other comprehensive income (loss) before tax	10	(4)	(12)
AOCI, balance at the end of the period	(18)	(28)	(24)
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	(12)	(16)
OCI before realized gains (losses) recognized in net income	(8)	14	7
Realized gains (losses) recognized in net income	(2)	(1)	(3)
OCI, portion attributable to Parent	(10)	13	4
AOCI, balance at the end of the period	(9)	1	(12)
Accumulated Other Comprehensive Income, Income Tax
AOCI, balance at the beginning of the period	1	(3)	(5)
OCI before realized gains (losses) recognized in net income	(3)	5	3
Realized gains (losses) recognized in net income	(1)	(1)	(1)
Income taxes on above of other comprehensive income (loss)	(4)	4	2
AOCI, balance at the end of the period	(3)	1	(3)
Accumulated Other Comprehensive Income, Net of Tax
AOCI, balance at the beginning of the period	0	(9)	(11)
OCI before realized gains (losses) recognized in net income	(5)	9	4
Realized gains (losses) recognized in net income	(1)	0	(2)
Other comprehensive income (loss) before tax	(6)	9	2
AOCI, balance at the end of the period	(6)	0	(9)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income, Before Tax
AOCI, balance at the beginning of the period	2,053	2,671	2,301
Investments OCI	531	(625)	384
Pension obligations OCI	16	(6)	(18)
Life deferred acquisition costs, life policy reserves and other OCI	(10)	13	4
Total OCI	537	(618)	370
AOCI, balance at the end of the period	2,590	2,053	2,671
Accumulated Other Comprehensive Income, Income Tax
AOCI, balance at the beginning of the period	709	927	797
Investments OCI	186	(220)	134
Pension obligations OCI	6	(2)	(6)
Life deferred acquisition costs, life policy reserves and other OCI	(4)	4	2
Total OCI	188	(218)	130
AOCI, balance at the end of the period	897	709	927
Accumulated Other Comprehensive Income, Net of Tax
AOCI, balance at the beginning of the period	1,344	1,744	1,504
Investments OCI	345	(405)	250
Pension obligations OCI	10	(4)	(12)
Life deferred acquisition costs, life policy reserves and other OCI	(6)	9	2
Total OCI	349	(400)	240
AOCI, balance at the end of the period	$ 1,693	$ 1,344	$ 1,744