Investments (Analysis Of Cost Or Amortized Cost Gross Unrealized Gains And Losses And Fair Value For Investments) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Fixed Maturities
Schedule of Available-for-sale Securities
Cost or amortized cost	$ 10,643	$ 10,314
Gross unrealized gains	174	409
Gross unrealized losses	128	24
Fair value	10,689	10,699
Fixed Maturities \| Corporate Securities
Schedule of Available-for-sale Securities
Cost or amortized cost	5,712	5,420
Gross unrealized gains	85	246
Gross unrealized losses	87	13
Fair value	5,710	5,653
Fixed Maturities \| States, Municipalities and Political Subdivisions
Schedule of Available-for-sale Securities
Cost or amortized cost	4,251	4,316
Gross unrealized gains	84	155
Gross unrealized losses	31	6
Fair value	4,304	4,465
Fixed Maturities \| Commercial Mortgage Backed Securities
Schedule of Available-for-sale Securities
Cost or amortized cost	287	280
Gross unrealized gains	3	7
Gross unrealized losses	2	1
Fair value	288	286
Fixed Maturities \| Government-Sponsored Enterprises
Schedule of Available-for-sale Securities
Cost or amortized cost	316	257
Gross unrealized gains	1	1
Gross unrealized losses	7	4
Fair value	310	254
Fixed Maturities \| United States Government
Schedule of Available-for-sale Securities
Cost or amortized cost	67	31
Gross unrealized gains	1	0
Gross unrealized losses	1	0
Fair value	67	31
Fixed Maturities \| Foreign Government
Schedule of Available-for-sale Securities
Cost or amortized cost	10	10
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Fair value	$ 10	10
Equity Securities
Schedule of Available-for-sale Securities
Cost or amortized cost		3,094
Gross unrealized gains		3,169
Gross unrealized losses		14
Fair value		6,249
Equity Securities \| Common Equities
Schedule of Available-for-sale Securities
Cost or amortized cost		2,918
Gross unrealized gains		3,135
Gross unrealized losses		14
Fair value		6,039
Equity Securities \| Nonredeemable Preferred Equities
Schedule of Available-for-sale Securities
Cost or amortized cost		176
Gross unrealized gains		34
Gross unrealized losses		0
Fair value		210
Fixed Maturities And Equity Securities
Schedule of Available-for-sale Securities
Cost or amortized cost		13,408
Gross unrealized gains		3,578
Gross unrealized losses		38
Fair value		$ 16,948

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in equity securities classified as available-for-sale.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=75030427&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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-Section 50
-Paragraph 5
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-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563

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-Publisher FASB
-Name Accounting Standards Codification
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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.2)
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