Investments Investments (Schedule Of Amortized Cost and Fair Value of Available-for-sale Securities and Related OTTI Recognized in AOCI) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Available for sale, at amortized cost	$ 78,630	$ 43,149
Available-for-sale,Gross Unrealized Gain	2,858	1,168
Available-for-sale, Gross Unrealized Depreciation	(130)	(730)
Available for sale, Fair Value	81,358	43,587
Available for sale, OTTI recognized in AOCI	(19)	(42)
US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale, at amortized cost	2,626	2,481
Available-for-sale,Gross Unrealized Gain	84	52
Available-for-sale, Gross Unrealized Depreciation	(2)	(5)
Available for sale, Fair Value	2,708	2,528
Available for sale, OTTI recognized in AOCI	0	0
Foreign Government Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale, at amortized cost	21,499	13,190
Available-for-sale,Gross Unrealized Gain	1,057	468
Available-for-sale, Gross Unrealized Depreciation	(48)	(213)
Available for sale, Fair Value	22,508	13,445
Available for sale, OTTI recognized in AOCI	(9)	(13)
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale, at amortized cost	22,860	15,028
Available-for-sale,Gross Unrealized Gain	977	355
Available-for-sale, Gross Unrealized Depreciation	(64)	(454)
Available for sale, Fair Value	23,773	14,929
Available for sale, OTTI recognized in AOCI	(9)	(28)
Collateralized Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale, at amortized cost	13,083	9,827
Available-for-sale,Gross Unrealized Gain	383	183
Available-for-sale, Gross Unrealized Depreciation	(5)	(52)
Available for sale, Fair Value	13,461	9,958
Available for sale, OTTI recognized in AOCI	(1)	(1)
US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale, at amortized cost	18,562	2,623
Available-for-sale,Gross Unrealized Gain	357	110
Available-for-sale, Gross Unrealized Depreciation	(11)	(6)
Available for sale, Fair Value	18,908	2,727
Available for sale, OTTI recognized in AOCI	$ 0	$ 0

Accumulated other comprehensive loss related to portion of other than temporary impairment (OTTI) due to factors other than credit losses on debt securities categorized as available-for-sale that an entity does not intend to sell and which it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis of the debt security. The amount represented by this item is net of tax, as applicable.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (aaa)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
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-Section 45
-Paragraph 14A
-URI http://asc.fasb.org/extlink&oid=66004124&loc=SL7669686-108580

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

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Amount of debt securities categorized neither as held-to-maturity nor trading.

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