Investments (Schedule Of Available-For-Sale Securities Whose Value Is Below Amortized Cost) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 security		Dec. 31, 2013 security
Available For Sale Securities In Unrealized Loss Position With Loss Severity Greater Than 20 Percent [Line Items]
Fair Value	$ 87,069		$ 80,976
Gross Unrealized Losses	460		1,265
Continuous Unrealized Loss Position, Total	10,962		20,161
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	298		416
Gross Unrealized Losses	98		115
Gross Unrealized OTTI	59		81
Number of Securities	97	[1]	101	[1]
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	48		1
Gross Unrealized Losses	19		1
Number of Securities	12	[1]	4	[1]
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	8		7
Gross Unrealized Losses	7		3
Number of Securities	3	[1]	1	[1]
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			59
Gross Unrealized Losses			19
Number of Securities			4	[1]
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	242		349
Gross Unrealized Losses	72		92
Gross Unrealized OTTI	$ 59		$ 81
Number of Securities	82	[1]	92	[1]

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