Investments Investments (Schedule Of Amortized Cost and Fair Value of Available-for-sale Securities and Related OTTI Recognized in AOCI) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Available for sale, at amortized cost	$ 80,119	$ 79,323
Available-for-sale,Gross Unrealized Gain	2,504	690
Available-for-sale, Gross Unrealized Depreciation	(213)	(1,543)
Available for sale, Fair Value	82,410	78,470
Available for sale, OTTI recognized in AOCI	(7)	(7)
U.S. Treasury and agency
Debt Securities, Available-for-sale [Line Items]
Available for sale, at amortized cost	3,545	4,158
Available-for-sale,Gross Unrealized Gain	97	30
Available-for-sale, Gross Unrealized Depreciation	(2)	(43)
Available for sale, Fair Value	3,640	4,145
Available for sale, OTTI recognized in AOCI	0	0
Foreign
Debt Securities, Available-for-sale [Line Items]
Available for sale, at amortized cost	21,777	21,370
Available-for-sale,Gross Unrealized Gain	942	395
Available-for-sale, Gross Unrealized Depreciation	(71)	(349)
Available for sale, Fair Value	22,648	21,416
Available for sale, OTTI recognized in AOCI	0	0
Corporate securities
Debt Securities, Available-for-sale [Line Items]
Available for sale, at amortized cost	28,940	27,183
Available-for-sale,Gross Unrealized Gain	891	150
Available-for-sale, Gross Unrealized Depreciation	(97)	(750)
Available for sale, Fair Value	29,734	26,583
Available for sale, OTTI recognized in AOCI	(6)	(6)
Mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Available for sale, at amortized cost	17,597	15,758
Available-for-sale,Gross Unrealized Gain	398	66
Available-for-sale, Gross Unrealized Depreciation	(29)	(284)
Available for sale, Fair Value	17,966	15,540
Available for sale, OTTI recognized in AOCI	(1)	(1)
States, municipalities, and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Available for sale, at amortized cost	8,260	10,854
Available-for-sale,Gross Unrealized Gain	176	49
Available-for-sale, Gross Unrealized Depreciation	(14)	(117)
Available for sale, Fair Value	8,422	10,786
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.

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