Investments (Schedule Of Available-For-Sale Securities Whose Value Is Below Amortized Cost) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 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	$ 83,792		$ 80,976
Gross Unrealized Losses	658		1,265
Continuous Unrealized Loss Position, Total	14,412		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	257		416
Gross Unrealized Losses	51		115
Gross Unrealized OTTI	78		81
Number of Securities	89	[1]	101	[1]
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	2		1
Gross Unrealized Losses	2		1
Number of Securities	5	[1]	4	[1]
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			7
Gross Unrealized Losses			3
Number of Securities			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	5		59
Gross Unrealized Losses	1		19
Number of Securities	2	[1]	4	[1]
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	250		349
Gross Unrealized Losses	48		92
Gross Unrealized OTTI	$ 78		$ 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.