Investments (Schedule Of Available-For-Sale Securities Whose Value Is Below Amortized Cost) (Details) $ in Millions		12 Months Ended
		Dec. 31, 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		$ 85,799	$ 87,069
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		1,852	298
Gross Unrealized Losses		907	123
Gross Unrealized OTTI		$ 17	$ 33
Number of Securities | security	[1]	219	97
Fair Value Decline, Greater Than 20% [Member] | Less than six months
Available For Sale Securities In Unrealized Loss Position With Loss Severity Greater Than 20 Percent [Line Items]
Fair Value		$ 1,584	$ 48
Gross Unrealized Losses		701	$ 19
Gross Unrealized OTTI		$ 2
Number of Securities | security	[1]	138	12
Fair Value Decline, Greater Than 20% [Member] | Six months or greater, but less than nine months
Available For Sale Securities In Unrealized Loss Position With Loss Severity Greater Than 20 Percent [Line Items]
Fair Value		$ 76	$ 8
Gross Unrealized Losses		$ 85	$ 7
Number of Securities | security	[1]	19	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		$ 39
Gross Unrealized Losses		$ 38
Number of Securities | security	[1]	2
Fair Value Decline, Greater Than 20% [Member] | Twelve months or greater
Available For Sale Securities In Unrealized Loss Position With Loss Severity Greater Than 20 Percent [Line Items]
Fair Value		$ 153	$ 242
Gross Unrealized Losses		83	97
Gross Unrealized OTTI		$ 15	$ 33
Number of Securities | security	[1]	60	82

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