Investments (Schedule Of Available-For-Sale Securities Whose Value Is Below Amortized Cost) (Details) $ in Millions		9 Months Ended	12 Months Ended
		Sep. 30, 2015 USD ($) security	Dec. 31, 2014 USD ($) security
Available For Sale Securities In Unrealized Loss Position With Loss Severity Greater Than 20 Percent [Line Items]
Fair Value		$ 86,346	$ 87,069
Continuous Unrealized Loss Position, Total		19,434	10,962
Fair Value Decline, Greater Than 20% [Member]
Available For Sale Securities In Unrealized Loss Position With Loss Severity Greater Than 20 Percent [Line Items]
Fair Value		1,137	298
Gross Unrealized Losses		507	123
Gross Unrealized OTTI		$ 24	$ 33
Number of Securities | security	[1]	172	97
Fair Value Decline, Greater Than 20% [Member] | Less Than Six Months [Member]
Available For Sale Securities In Unrealized Loss Position With Loss Severity Greater Than 20 Percent [Line Items]
Fair Value		$ 932	$ 48
Gross Unrealized Losses		397	$ 19
Gross Unrealized OTTI		$ 3
Number of Securities | security	[1]	103	12
Fair Value Decline, Greater Than 20% [Member] | Six Months Or Greater, But Less Than Nine Months [Member]
Available For Sale Securities In Unrealized Loss Position With Loss Severity Greater Than 20 Percent [Line Items]
Fair Value		$ 45	$ 8
Gross Unrealized Losses		$ 31	$ 7
Number of Securities | security	[1]	3	3
Fair Value Decline, Greater Than 20% [Member] | Nine months or greater, but less than twelve months
Available For Sale Securities In Unrealized Loss Position With Loss Severity Greater Than 20 Percent [Line Items]
Fair Value		$ 8
Gross Unrealized Losses		5
Gross Unrealized OTTI		$ 2
Number of Securities | security	[1]	7
Fair Value Decline, Greater Than 20% [Member] | Twelve Months Or Greater [Member]
Available For Sale Securities In Unrealized Loss Position With Loss Severity Greater Than 20 Percent [Line Items]
Fair Value		$ 152	$ 242
Gross Unrealized Losses		74	97
Gross Unrealized OTTI		$ 19	$ 33
Number of Securities | security	[1]	59	82

[1] We may reflect a security in more than one aging category based on various purchase dates.