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, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Available for sale, at amortized cost	$ 82,036	$ 79,323
Available-for-sale,Gross Unrealized Gain	3,210	690
Available-for-sale, Gross Unrealized Depreciation	(202)	(1,543)
Available for sale, Fair Value	85,044	78,470
Available for sale, OTTI recognized in AOCI	(32)	(7)
U.S. Treasury and agency
Debt Securities, Available-for-sale [Line Items]
Available for sale, at amortized cost	3,438	4,158
Available-for-sale,Gross Unrealized Gain	133	30
Available-for-sale, Gross Unrealized Depreciation	(1)	(43)
Available for sale, Fair Value	3,570	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	21,974	21,370
Available-for-sale,Gross Unrealized Gain	1,171	395
Available-for-sale, Gross Unrealized Depreciation	(68)	(349)
Available for sale, Fair Value	23,077	21,416
Available for sale, OTTI recognized in AOCI	(27)	0
Corporate securities
Debt Securities, Available-for-sale [Line Items]
Available for sale, at amortized cost	30,344	27,183
Available-for-sale,Gross Unrealized Gain	1,131	150
Available-for-sale, Gross Unrealized Depreciation	(108)	(750)
Available for sale, Fair Value	31,367	26,583
Available for sale, OTTI recognized in AOCI	(5)	(6)
Mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Available for sale, at amortized cost	18,457	15,758
Available-for-sale,Gross Unrealized Gain	570	66
Available-for-sale, Gross Unrealized Depreciation	(13)	(284)
Available for sale, Fair Value	19,014	15,540
Available for sale, OTTI recognized in AOCI	0	(1)
States, municipalities, and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Available for sale, at amortized cost	7,823	10,854
Available-for-sale,Gross Unrealized Gain	205	49
Available-for-sale, Gross Unrealized Depreciation	(12)	(117)
Available for sale, Fair Value	8,016	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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